


Revision

by Kadigan



Category: Iron Man (Movies), Marvel Avengers Movies Universe
Genre: Afghanistan, Aftermath of Torture, Arc Reactor, Canonical Character Death, Explicit Language, Extended Scene, Gen, Hurt/Comfort, Implants, Injury, Medical, Medical Procedures, Missing Scene, Rather dark but ultimately canon-compliant, Surgery, The author is a woman who regrets everything... and nothing, Tony Feels, Torture, Yinsen feels, heart problems
Language: English
Status: In-Progress
Published: 2012-10-24
Updated: 2016-04-11
Packaged: 2017-11-16 22:52:07
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, Graphic Depictions Of Violence
Chapters: 15
Words: 42,506
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/544720
Author URL: https://archiveofourown.org/users/Kadigan/pseuds/Kadigan
Summary: <blockquote class="userstuff">
              <p>
  <i>This time, when they drag Stark back in and toss him on the floor, he doesn't get back up.</i>
</p><p>Tony Stark awoke in a cave with a magnet in his ribcage and a timer counting away his life. Without Yinsen's help and his own engineering genius, he would not have lived a week. Instead, he tore his way out from under the mountain. Between the magnet and the escape, though, lay three months of hell...</p>
            </blockquote>





	1. Diagnosis

**Author's Note:**

> Rated for some strong language and a lot of violence. See the tags for more specific warnings. Also, I've tried to do my homework, but I am not a doctor.
> 
> I don't own these characters or the universe they live in -- I'm just borrowing them for a while. I promise to return them in approximately the same condition I found them. No, really. The scars will fade.

**Notes for the Chapter:**

> (diagnosis: the identification of a problem by examining its symptoms)

This time, when they drag Stark back in and toss him on the floor, he doesn’t get back up.

For the first few minutes, this is normal. Yinsen knows very well what Raza’s goons are doing to Stark in that other room, and the man is not made of iron. When they haul him back and dump him, he’s strung out on shock and pain and terror, and he barely knows where he is. The first time, when Yinsen had tried to go immediately to his aid, Stark had lashed out blindly and nearly broken his glasses. Since then, they both know to give him several minutes to collect himself. When he gathers the strength for a sarcastic remark, however weak and thin, Yinsen knows that he’s present again; he takes that as the signal to go to his patient, give him a towel, and help him onto a cot. It never takes more than a few minutes.

This has been more than a few minutes. When Yinsen realizes how long Stark’s gone without a quip, he turns to frown at him. The other man is still huddled on his knees by the door, dripping wet and shivering violently. However vicious the implications, this is normal.

The waxy, gray pallor of his skin is not.

Yinsen’s frown deepens, and he goes to Stark, drops down beside him. Stark is looking up at him, panting thinly for breath. His hands lie limp at his sides; he evidently doesn’t have the strength to lift them. He’s tracking Yinsen, though, and his pupils are equal. This isn’t confusion, or shock.

The doctor reaches for the pulse in his wrist, and there’s the answer. Stark’s heart is hammering, a faltering flutter as fast as a bird's. His breathing’s too fast and too shallow; there’s a liquid wheeze under it, water from the dunkings. Within a dozen more racing, uneven beats, Yinsen knows: this will not last. Stark’s heart is giving out as he watches.

What did they _do_ to him this time?

There’s no time to speculate—he has to act immediately. Cardioversion with a car battery and half a dose of atropine won’t be a pleasant business, but he’s damned if he’ll let Stark die _now._

Yinsen surges to his feet and pounds on the metal door.

\---

Tony can’t feel his fingers or toes. Breathing doesn’t seem to be doing very much, either. Worse, he _can_ feel his heart beating: each labored thud rattles his ribs and makes his whole chest burn. He can count every one of the still-raw shrapnel wounds, and the electromagnet weighs down his core like furnace-hot stone.

Above and behind him, the surgeon who saved him is arguing with someone in Dari. Tony only catches a few words over his own wet panting: _heart, water, now, bad._ The argument ends, the door booms hollowly shut, and a thin hand lands on his shoulder. “Stark. Keep breathing. They’re bringing my kit.”

He tries to nod. His head might have moved; he isn’t sure. Any more effort and he’d have grayed out again.

Two hands now, on his shoulder and his back; they’re pulling his wet shirt over his head, pushing him down to lie on the floor. The cold stone does not help _anything,_ but—yeah, his head’s a little clearer, lying down like this. When the doctor looms over him, grabbing his wrist with one hand and urging him with the other to tilt his head back, he can actually make out the details of the doctor’s face.

Things still blur together a bit. The doctor’s lilting accent ordering him to cough— _bad idea_ , they both find, with his lungs still soaked and screaming from the hours-long struggle for air. Fingers pressing on the pulse point in his throat, just on one side—which, weirdly, seems to help a little. Above all, the slow grayness creeping in at the edges of his vision, and the agonized lurch of his heartbeat.

Metal goes _boom_ somewhere; he feels it more than hears it. Sharp pinch in the back of his hand. He's rolled onto his side.

The doc’s touching the electromagnet housing. Tony knows—he can feel the back of the thing where it's sunk against his sternum, aching invasive pressure where nothing should be allowed to go. (The touch is sickening, _wrong,_ almost as bad as the thunder of his heartbeat.) More than that, he can just about see the doctor's hands, and they're doing something to the battery leads.

"I'm going to disconnect you for a moment. Just a few seconds. You shouldn't feel that, but the next part is going to hurt."

Tony doesn't have the time or strength to say _no, what the fuck?,_ but he does manage a hitching gasp--

And in one quick movement, the doctor pulls one of the leads off the magnet, wedges the butt of a steel forceps between the other lead and the magnet's metal housing, and taps the bare wire on the center of Tony’s back.

Lightning strikes. Tony convulses. The electricity sears through him, his muscles wrenching as if to rip free of his bones, and his vision goes white.

He's pretty sure he loses some time, after that.

\---

Stark spasms once when Yinsen shocks him, eyes huge and dark, and then loses consciousness. There isn't time to worry about it. Instead, Yinsen pulls back the wire and presses the stethoscope from his kit against the man's chest, just beside the silent magnet, to listen hard for the heartbeat.

It's stable. The rhythm is steady and blessedly normal.

Yinsen breathes a prayer of thanks, even as he pulls the forceps away and twists the loose wire back into place. The magnet hums back into life. Stark doesn't stir then, nor when Yinsen brings the thin, scratchy towel from their basin and tosses it over him, nor when the doctor turns back to his kit for rubber gloves and antiseptic. When he touches the small round burn on Stark's back, though, even the cool gel doesn't stifle the groan of protest.

"Back with me, Stark?"

Glassy brown eyes open to slits. "...th'hell wuzzat?"

"Cardioversion." Yinsen covers the burn with ointment, then tapes a square of gauze over it. "You were having an episode of ventricular tachycardia. I used an electrical shock to reestablish your normal heart rhythm."

Stark grunts in what might be assent and lets his eyes fall shut again. For a moment it’s quiet, just the distant drip of water and the hum of the car battery and the steady pulse against Yinsen’s fingertips.

“ ’m gonna need'jer help w’this one,” Stark rasps.

“Yes, you are.” Yinsen looks down at him with a grim, tight smile. “Your heart is failing, Stark. There’s been some arrhythmia since your initial surgery, from the trauma and the electromagnet, but this is much worse."

“Tell me about it.” Stark attempts a chuckle. It comes out as more of a pained cough. "What can...?"

“What can I do? Not much.” Yinsen stands, running a hand roughly back over his scalp. “I don’t even have the tools for proper diagnosis here. They gave me what I needed to keep you alive—”

“ ’s gonna kill me again, isn’it?—”

“And how much will they care, if you still refuse to build for them? You need a pacemaker, Stark.” Yinsen hasn’t sugarcoated anything else about the man’s condition. Why start now? If the news elicits a flinch, why, it damned well should. “You need a pacemaker, if not an ICD, and I need the tools to implant one. I do not think they will give me very much to work with.”

Stark is silent at that, just watching him, and Yinsen sees something dark sink behind the other’s eyes.

\---

The next time they take him, Tony breaks.

\---  
\------  
\---

[TBC]

**Notes for the Chapter:**

> I blame Tumblr for this. No, really. There were these two posts -- http://loving-that-officey-feel.tumblr.com/post/17895251794 and http://loving-that-officey-feel.tumblr.com/post/12870614841/ . I read them a week or so ago, and suddenly PLOTBUNNIES EVERYWHERE.
> 
> To summarize those posts, loving-that-officey-feel thought over the medical implications of Tony's arc. She considered the hell he must have gone through to put it there and then immediately tear his way out of that cave. Hello, new headcanon. I was instantly inspired. (If "we only hurt the ones we love", I must be head-over-heels for Tony Stark. Like that's a surprise. Dammit.)
> 
> This fic will explore that headcanon and its consequences, following Tony and Yinsen through the spaces between what the movie shows us of Afghanistan.


	2. Point of Inflection

**Summary for the Chapter:**

> _Where'd they_ get _it all? SI doesn't double-deal. He didn't hear about any missing shipments. Nothing this big, anyway—there's enough here to sink a city._
> 
> _...Or build a Jericho missile. Yeah. Okay. He should've seen that one coming._

**Notes for the Chapter:**

> (point of inflection: a point where higher-order trends change) 

They give him a little longer to rest this time, right after the doctor and that fucking _car battery_ kick his heart back into gear: he gets a whole two hours. Joy. It’s long enough that by the time they come for him, he can stand, and even carry the battery if he works at it. They still send two guys to haul him off the cot, not expecting his legs to hold him anymore.

The thugs drag him into the other room and shove him to his knees in front of That Barrel. One of their hands thumps against the battery he’s clutching, making it dig hard into the inflamed skin around the healing incisions: he twitches, but it’s not enough to take his focus off the water. Not much could do that right now.

The water is black and glints in the cave’s harsh shadows. Still. Patient.

“Build me the Jericho,” someone hisses in his ear.

“No,” he rasps, half defiance and half plea.

They shove his head down for the hundredth time, and everything fractures again.

It’s ice and agony and no air, darkness and slivers of rotting greenish light, shouts muffled through the water and his own frantic grunts loud in his ears. It’s the straining of his desperate lungs and the grind of his sawn-open chest, fighting the wet sucking void inside. It’s his heart thrashing against his ribs like a wild desperate animal. It’s the darts of frenetic agony that jolt through him whenever water splashes over the magnet’s contacts, making him convulse in the thugs’ grip, stopping his heart for whole seconds. It’s the futile struggle for air, warmth, air breath _air LIFE—_

there’s no air _he can’t breathe_

—they haul him back up to the surface.

His desperate gasps are splitting his chest wide open, but he still can’t gulp air fast enough. It’s never tasted sweeter. He’ll only get a few breaths. His arms have loosened, and he's nearly dropped the battery: he crushes it against his broken ribs, more willing to deal with that sharp pain than with the horror of losing his power source.

In his ear, a hissing voice: “Build me the Jericho.”

 _Oh, God._ “No.”

They shove him under again. It feels like even longer this time, and phosphenes are boiling at the rim of his vision when they jerk him back up.

"Build me the Jericho."

Between hacking up mouthfuls of water, he manages a "no".

Again. His vision’s gone completely white, and his heart is trying to shove the magnet out of his chest.

"Build me the Jericho."

This time he can only swallow a whimper.

Again. "Build me the Jericho."

Again. "Build me the Jericho."

Again, and longer than ever before. There's nothing but the water, nothing but the impossible dream of air, but somehow he remains keenly aware of his thundering heart. It's going to burst. It's going to explode in his chest. He’s going to die. He's going to die _here—_

Air, and the voice in his ear, so close that the heat of its breath boils his skin. _"Build me the Jericho!"_

 _"Okay!"_ It’s a ragged whisper, torn from his throat between sodden coughs, but he's forcing it out with all the strength he has left. "I'll build it! Just _stop!"_

For a keening, horrible instant, he's afraid they don't care. He can't see, he can barely hear or feel; he wouldn't know it was coming.

It doesn’t. They heard him. He hacks up another lungful of water, and tries not to faint with relief.

\---

Four hours after Stark's cardiac episode, the door to their cell bangs open and the guards toss him back inside. He lands on the floor in a nerveless, boneless heap of dripping black hair and ashen skin, the battery clattering to the ground beside him. He coughs weakly, with a worrisome gurgle, and one hand twitches uselessly towards his chest. Yinsen takes one look at him and goes for the forceps.

Five unpleasant minutes later, there's another burn on Stark's back, but his heart is beating normally again and Yinsen has him laid out on the cot. His eyes flicker open; blown pupils turn them into glassy black pits.

"I broke."

The doctor hums noncommittally, occupied with treating the fresh burn.

"I _broke,"_ Stark rasps again, trying to turn his head. He squeezes his eyes shut; his face twists, and it isn't just the pain. "Told 'm I'd build th'Jericho."

The look on his face gives Yinsen pause. He hasn't seen that kind of self-loathing since... well, since right after _it_ happened. The ashes hadn’t cooled yet, and he’d looked in the mirror...

Stark is still trying to turn towards him. Yinsen puts a hand on his shoulder, quelling but not ungentle. "Hold still. I need to treat this." He lets the hand linger a moment, though, and quietly adds: "Everyone breaks, Stark. It was only a matter of time."

Somehow, that doesn't give either of them much comfort.

\---

Tony must have fallen asleep—or passed out, he's not sure—for a bit while the doctor poked at his back, because when the _boom_ of the door wakes him, his hair's mostly dry. That's good. It would have sucked to get a bag shoved over his head with his hair still wet. The damp just gets everywhere, and it’s cold enough in here when he’s dry. Not to mention the bed-head. Artfully disheveled is a good look on him, but there’s no “artful” in a burlap sack.

...and just who is he kidding, fixating on that?

Resting did him good, though. He's hardly staggering at all as they shove him out the door and down what must be a quarter-mile of tunnels. They drag him into a diffuse light, and someone yanks the bag off.

Whoa. _That's_ bright.

When he's a little bit less blind, he starts to take it all in, and right then his priorities readjust themselves. His rattling lungs and the thugs' shoving are suddenly a lot less important compared to the arsenal cached in front of him. Jesus _Christ,_ they've got a lot of his weapons.

He says so, when the big beardy slug asks his opinion. They've dragged the doctor along, too, so Tony can follow his expression as he translates. It’s telling. The doc doesn't trust these guys any farther than Tony does. (Admittedly, he’d sort of figured that out already, what with the fear in the doc’s hissed “do as I do!”. Still. It’s nice to have confirmation of the guy’s loyalties, not to mention Tony’s fantastic observational skills.)

Where'd they get it all? SI doesn't double-deal. He didn't hear about any missing shipments. Nothing this big, anyway—there's enough here to sink a city.

...Or build a Jericho missile. Yeah. Okay. He should've seen that one coming.

Shit. There isn't going to be any delay while they get him the parts, then. It's too late to refuse again—he wouldn't survive it. He's really going to have to build a Jericho, the thing that should've kept Americans safe around here for a generation, and he's going to have to give it to these bastards.

The big beardy guy is sticking out his hand and smiling, like he’s looking to close some kind of business transaction. Tony's going to have to build it _now._

_Shit._

\---

The Ten Rings are satisfied with Stark’s assent—it’s lucky that no one in earshot speaks English—but they still throw the bag over his head before taking him back to the cell. They’re about to do the same to Yinsen, but he raises a hand and calls out in Farsi: “Wait a moment.”

The one in front of him just frowns and says something in rapid-fire Czech. Thankfully, Abu Bakaar is close enough to overhear. "What do you want, doctor?"

Yinsen draws a long breath. “Stark’s heart is failing. I need to operate again.”

His captor just tilts his head, projecting unconcern, but Yinsen doesn’t think he’s imagining that worried twitch trying to furrow Bakaar’s brow. “Your earlier work was not enough, then?”

“The situation changed.” _You’ve been drowning and electrocuting a man recovering from penetrating thoracic trauma,_ Yinsen doesn’t say; he is not suicidal enough to point out that the blame lies on the men holding the guns, especially when one of them is already questioning his usefulness. _What did you think would happen?_ “I couldn’t have predicted that.

“But the fact remains that if you want him to live long enough to build your missile, I have to operate. I’ll need my kit, the supplies, assistants, a suitable theater. And he will need time to recover afterwards.” He chokes down his pride, and the loathsome feeling of begging anything from this man: “Please.”

Bakaar doesn’t appear to be feeling any more homicidal than usual, but he clearly isn’t convinced, either. He gives a noncommittal hum and folds his beefy arms. “I will consider your request.”

The Czech guard takes that as his signal to march Yinsen back to the cell.

\---

By the time they push the surgeon in behind him, Tony’s hunkered down in front of the coal burner and wrapped in a blanket. The doc’s quiet sigh, and the movement as he stokes the fire, don’t really penetrate the whirl of Tony’s thoughts. There has to be a way out of all this, and he could find it if he could just _think!_

Right now, though, that’s easier said than done. He’s never been this tired in his life, and he knows tired. (He graduated MIT at seventeen. All-nighters are his old friends.) Every time he manages to grasp a handful of thoughts and start to combine them, he’ll cough again, or shiver, and his ribs will grind and the thoughts will skitter out between his fingers.

He’d probably give his whole fortune right now for some decent heating and a bottle of aspirin.

Suddenly, the doctor speaks. “I’m sure they’re looking for you, Stark. But they will never find you in these mountains.”

Oh, he knows. He designed half the equipment they’re using to search for him. It’s his job to know _exactly_ how hard it is to find anything in these godawful hills.

When that doesn’t get much of a response, the surgeon crouches to look Tony in the eye. His own expression is suddenly tense and somehow pained. “Look, what you just saw—that is your legacy, Stark. Your life’s work, in the hands of those murderers! Is that how you want to go out?” His voice twists, like he’s disappointed in Tony— _offended,_ even, by his defeat. It’s pretty rich, coming from the guy whose life isn’t measured in the time til the Energizer Bunny runs down. “Is _this_ the last act of defiance of the great Tony Stark?”

Then the doctor’s final sentence hardens into something cold and driving. He throws it down at Tony’s feet: “Or are you going to _do something about it?”_

Tony’s already shaking his head before the words are out. “Why should I do anything? They’re gonna kill me—you—anyway, and if they don’t I’ll probably be dead in a week.”

The doctor glares at him, sharp and fierce. “Then this is a very important week for you, isn’t it?”

Of course it is. He’ll be dead at the end of it.

Hell, what could he accomplish in a week, anyway? It took longer than that to get the Jericho even halfway prototyped. He was a week in before he caught the mass-ratio issues with the secondary sabot. Another three days to miniaturize, one more to fix the power couplings, and that was with Pepper to run interference so he could stretch the deadline...

Oh.

_Oh._

Hold that thought. He’s got an _idea._

\---  
\------  
\---

[TBC]


	3. Analysis

**Summary for the Chapter:**

> _He cuts. He solders. He welds, coils, hammers, carves, molds, files, glues, etches,_ builds. _The device takes shape under his fingers._

**Notes for the Chapter:**

> (analysis: a detailed examination of a problem's elements or structure)

Their cell is absolutely bustling, as much with information as activity. The Ten Rings are everywhere, moving heavy equipment, hauling crates of guns, unpacking hand tools, toting missiles that could blow them all sky-high. Stark’s matching all of them together for sheer energy, firing off endless demands for supplies, equipment, and working conditions. It’s all Yinsen can do to keep up with him. Trying to translate the man’s machine-gun rattle of jargon and colloquialisms is quite bad enough in itself: add in the problem of switching languages on the fly, so as to be comprehensible to whichever of Raza’s men needs to hear these particular instructions, and the doctor’s nearly reduced to stammering shorthand.

Yinsen has never seen Stark in a working mood before. It’s turned him into a different man. This certainly isn’t the spoiled libertine he’d met in Bern, nor the broken captive he baited last night. Stark hadn’t said a word to Yinsen’s jabs about his passivity, but something had ignited under his skin: he’d stared into the fire for hours, fingers twitching around faraway tools, and risen in the small hours of the morning to don a grim, manic smile and scrawl a long list of materials. Bakaar had eyed his prisoner with suspicion, but ordered the men to start assembling the requested items.

Somehow, the moment there was work to be done, Stark had taken over. He’d moved the process along with driving, driven grace, intent on the task at hand and still planning six steps ahead. He’d made himself the center of all the bustle, gravitationally so, and he managed the work and the materials with effortless charisma. Yinsen thinks of a carpet-weaver he once watched at work, the way her hands had selected each thread, sharp, spare, and certain; somehow, she had woven a breathtakingly intricate pattern with impossibly few movements, as if her hands were just a conduit for her fierce concentration. Stark is like that now, his focus and drive palpable through every movement in the workshop.

Whatever he’s planning to build, Yinsen would bet his freedom that it isn’t the Jericho.

The man is frustratingly close-lipped about his actual plans, though. He orders Yinsen around casually, as though the doctor’s his hired gofer, and brushes off all inquiries into the purpose of the tasks he sets. Yinsen breaks down eleven rockets, each probably worth more than he’d made the previous year, for tiny slips of palladium. (Unlike Stark, he avoids destroying anything not immediately necessary.) He dissects a sensor package apparently intended for some kind of aircraft, and after two hours’ work manages to free an intricate coil of copper wire; Stark tells him to toss it in the corner of a workbench, since they won’t need it for a few days. Try as he might, Yinsen cannot fathom how all this may come together. It would probably make more sense if he were an engineer.

An engineer may not have spotted Stark’s growing distress, though. From the corner of his eye, Yinsen watches Stark all day long, carefully tracking the sheen of cold sweat on his forehead and the tremble in his left hand. By mid-afternoon, he’s as gray as the stone behind him. When it takes him four tries to get his forceps around the last palladium strip, Yinsen decides that he's had enough. “You should rest.”

Stark jumps, startled out of his concentration, and twists around to face Yinsen. He almost succeeds in hiding the pain of the sudden motion. “What? No. No, I'm fine. Got a lot to do—”

“You're about an hour away from collapse.” The doctor reaches for the pulse in Stark’s wrist, making sure to do so within line of sight and to telegraph his intentions. Uncomfortably fast and a little erratic: it isn't dangerous yet, but it could get there very quickly. The muscles of the engineer's forearm are drawn tense and quivering.

“Yeah, and half an hour from getting this part together. I’ll rest in a minute, promise, Mom.” He disengages from Yinsen’s hand with a dismissive little wrist-flick. Halfway through turning back to face his work, though, he freezes and goes white to the lips. “Mother _fucker,”_ he hisses, breathing in tiny shallow pants.

Yinsen sighs under his breath and goes to fetch Stark's pillow. The man manages a skeptical, uncomprehending look when Yinsen holds it out. “Hold it to your chest,” the doctor explains, giving it a little shake. “You'll feel better with your ribs supported.”

The effort of reaching for the pillow makes drops of sweat roll down Stark's temples, but he hugs it close, and after a moment his breathing starts to ease. He lets his eyes fall shut. “Shit,” he murmurs... and, unbelievably, finishes turning around to reach tremulously for his forceps.

“What— _No,_ Stark,” Yinsen snaps, flattening his hand over the tweezers. "You can't work like this."

Stark just reaches right over him to pick up a different pair. “Sure I can. I can lecture while smashed, why not cast palladium with broken ribs? Chill. It'll be fine.” Yinsen opens his mouth to object, and Stark looks him straight in the eye. The determination in that look hits him like a fact, something completely inarguable. Stark is not going to be swayed.

...Half an hour. All right. He’ll just have to be prepared for Stark’s next collapse.

\---

The job at hand takes exactly thirty-six minutes. When he’s wrapped it all up—the palladium gathered, the crucible cleaned, the mold prepared—Tony brushes greensand off his hands, deliberately ignoring their violent tremors, and gingerly straightens up on the stool. The clarity of work-to-be-done is fading fast, and he’s beginning to notice the grind of his ribs again. He picks the pillow up from his lap and hugs it to his chest. It helps a little.

Across the room, the doctor catches his eye and motions him over. It looks like the guy rearranged their cots after he finished breaking down the last of the Shrike SAMs. Tony’s is closer to the workbenches now.

Huh. That’s kind of nice.

Tony takes the invitation—he really does hurt, and yeah, he could use a break—and shuffles arthritically across the cell to lie down. The doctor looms over him, giving him a flat stare. The guy’s got something to say. Tony waits, hoping his _go ahead already_ comes through in his face.

Finally: “Why are you really working so hard?” The doctor folds his hands and glares at Tony. “I think we both know you're not actually this excited about building their missile.”

For a moment, Tony panics—ugh, he actually felt his heart leap, that's unpleasant—but then he realizes that Doc wasn't just moving the cot for Tony's comfort. The way they're posed now, the surgeon’s back is to the camera, and there's a tabletop blocking its view of Tony's face. _Huh. Nice._

...and you know, he's going to have to tell sooner or later.

“Okay.” Tony exhales. Slowly, to keep the strain off his ribs. “Right. You're right, it's not the missile. It's just...”

He curls his fingers against the canvas. “Look, okay, it's gonna take me more than a week to build anything big, right? And we both know I'm not gonna last that long.” He tries to smile. It comes out wry, pained, and not remotely mirthful. “So I've gotta build a better mousetrap.”

He shuts his eyes. Slow breaths. Review the blueprints in his head. His hands twitch at his sides, itching for a soldering gun and a pair of pliers. “And I'm gonna need your help.”

Slow breaths. Don't think about what that means. _Don't._

The doctor shifts his weight to the other foot. “What do you need?”

“Just information for now. The hard part comes later.” And like hell is he talking about _that_ any sooner than he has to. “First, I'm gonna need construction drawings for this thing—” he indicates the magnet— “and the substrate it's embedded in.”

“The subst... what, your chest?” The doc's raised eyebrow is actually audible.

“Yeah. Before and after, that'd be best. Normal human chest cavity and then one with all these modifications. I need to know what I'm working with here. And maybe you can't draw, whatever, at least tell me about it so I can draw it myself. Just gotta know the specs.”

“What do you need them for? Surely I could simply help design—”

Tony cuts him off. “And one last thing. You've gotta let me work. I know it's gross watching me like this—” he sweeps a shaky hand over his clammy pallid skin, his wet labored breathing, his faltering heart— “but I'm trying to extend our deadline. If it isn't actually gonna kill me faster, I don't care if I fall over, just patch me up and get me back on the job.”

There's a long, long silence. Eventually Tony has to crack open one eye and look up, just to make sure that the doctor didn't spontaneously die or something—the guy's been quiet long enough. He's still there, looming over Tony and studying his face; Doc’s brow is furrowed deep and his eyes are narrow, searching.

“All right,” he says finally. “What will I be using for paper?”

\---

Yinsen doesn’t just hover while Stark falls asleep, heading instead to one of the workbenches to unroll a few sheets of the stiff, disconcertingly-waxy paper the Rings provided. Back at the bench above Stark’s cot, he settles in to draw. Slowly, the ghost of a human thorax coalesces on the page: curves of rib and stomach and aortic arch, rough hatching of interlocking vertebrae, broad arrows for the grain of muscle tissue. He is at best a passable artist, but the shapes of human anatomy are etched so deeply into his mind and his hands that he can find ways to translate. Now and then, he leans over to check the details against the lines of his sleeping patient’s chest.

Yinsen does not understand this man. He had thought he knew Stark: a drunken lecture in Bern, casual arrogance in the news, genius tools of murder sold without thought for the consequences. Brilliance is the only similarity to the man now lying on the cot, so diminished in repose that the cave feels dimmed. Yinsen had not expected the genuine shock when Stark met his legacy. He had not expected it to sublimate into such burning drive. He had not expected to discover morality under the playboy exterior.

He certainly hadn’t expected Stark to start earning his respect.

Two hours in, Stark jolts himself awake with a yelp. Yinsen only looks up from his annotations and cocks an eyebrow.

“M’fine.” Stark scrubs one hand over his eyes, wiping a film of sweat off his too-pale forehead, and levers himself up to sit on the cot. For a moment he’s still, letting the weight of sleep slough off. Yinsen can almost see the engineer’s focus rising up to replace it; when Stark swings his legs off the cot and stands, it’s in one nearly-fluid motion, and he heads for his workbench with that same driving grace.

With Stark awake and working, the workshop-cell is alight again. Yinsen finds himself working more efficiently, more easily: Stark’s energy is contagious. He resolutely does not analyze this fact.

He _does_ analyze his own reactions when, quite some time later, Stark’s voice startles him out of his work: “Hey, Doc. You ever cast metal before?”

Yinsen startles, nearly dropping his pen. “What? No.” He glances at the clock. _Three more hours?_ That rattles him. It’s not safe to lose track of time around here. How did that happen?

“Never too late to learn. C’mere, that can wait.”

Yinsen just stares, completely blank, for a moment. He lost track of time, _three hours’_ worth of it, and he is neither terrified nor furious. How does Stark _do_ that?

Then he sighs, puts aside his work, and moves over to Stark’s workstation. The engineer is fidgeting with a sheet of paper covered in calculations. A ceramic crucible sits in front of him, next to a heavy bowl of something deep red and sandy; inside the crucible, twelve strips of silver metal gleam. “Yes?”

“I need your help with this next part. It takes steady hands, okay?” He continues without waiting for an answer, talking right over the agitated ruffle of the paper in his shaking fingers. “CliffsNotes version, we’re gonna build up this fire, melt the palladium over it, and pour it into this mold. I’ll watch the fire, you just have to take the tongs when I tell you and then pour.”

Yinsen nods, and they begin to build up the forge.

\---

The contents of the crucible are well and truly molten now. Tony squints through the brutal wall of heat over the forge, assessing the metal’s precise state and the color of its glow. Yes, it’s time: he gives the doctor a significant nod.

God, he wishes he could do this part himself. His fingers actually ache with it, the itching need to handle such a crucial step personally. If they’d quit fucking shaking, he _could_ be doing it himself. “Careful,” he blurts. “Careful, we only get one shot at this.”

“Relax,” Doc breathes, smiling. Incredibly, he seems to be taking his own advice. “I have steady hands. Why do you think you’re still alive, hm?”

Right. He’s a surgeon. A life hanging on his manual dexterity—he was literally trained for this.

The knowledge is enough to let Tony stop hovering within six inches of the guy’s side, moving all the way out to eighteen inches as they move to the workbench. He lets the battery clack gently onto the benchtop, still wanting his hands free if something should happen.

They both bend close over the mold as the doctor starts to pour. Tony stares without blinking, barely breathing; his world has narrowed to the radiant heat off the molten metal and its glow streaming out of the crucible. His life depends on the next few seconds, on that metal going where it should, and he can’t control it. He can’t even help. _Jesus fuck, let him get this right!_

The sight of that thin silver stream flowing into his mold, hitting the sprue dead-on, nearly grays him out with relief.

You know, that’s twice now that this guy has saved his life. The little voice of his common sense and social skills prods him as they watch the metal fall. (He dubbed that one his Inner Pepper, he remembers with a pang, and then shuts the thought down because thinking of Pepper is _not helping_.) “So what do I call you?” he hears himself ask.

“My name is Yinsen.”

Tony repeats the name, and the last of the palladium vanishes under the greensand. He finally tears himself away from it, tilting his head to look Yinsen in the eye. “Nice to meet you.”

The doctor straightens up with a crooked, genuinely amused smile. “Nice to meet you too.”

\---

Yinsen wakes from a shallow doze into an overwhelming certainty that something is wrong.

His imprisonment here has taught him to trust that instinct. He sits up and scans all corners of the cell. The doors are closed and locked; no one is knocking. Nothing is on fire. Stark is...

Stark is seated at his workstation, slumped over the benchtop. A soldering iron and some intricate toroidal device lie abandoned beside his right hand as if pushed hurriedly out of the way. Two fingers of his left hand are hooked into his shirt collar, their weight tugging it away from the magnet. His eyes are wide open and completely sightless; his face is ash-white and clammy, his mouth open as he gasps noisily for breath.

Yinsen is at his side almost before he registers moving. “Stark! Say something.”

Stark mumbles something unintelligible. Under Yinsen’s fingers, his pulse bounds like a rock skipping down a mountainside. Another cardiac episode, and this one apparently spontaneous.

“Come on. Let’s get you down.” Yinsen reaches to grasp Stark’s shoulders.

The man blinks hard, and his eyes come back into focus. “Nuh. M’fine. Jussasec,” he slurs, twitching weakly away from Yinsen’s hands.

The doctor ignores him, instead starting to move him off the stool. Yinsen is going to have to shock him again. He’ll need to be lying down—

Stark’s eyes snap wide open. He drags in a deep, deep breath that bells his chest out and half uncurls his spine, then jerks out of Yinsen’s grip to sit bolt upright. His breathing evens out, still shuddering a little but quickly losing that ominous rattle. Color begins to flush back into his skin. Yinsen grabs for his pulse again: it’s nearly normal.

A thin curl of smoke rises from the tip of the abandoned soldering iron. With a shaking hand, Stark fumbles for its off switch. “Shit,” he breathes, bracing himself over one forearm.

Yinsen is already looping Stark’s other arm over his own shoulder. “Come on. Up.” He’s not built for heavy lifting, but thankfully, neither is Stark, and this isn’t the first time he’s had to carry the man to a cot. When he has his patient lying down, he goes for his kit.

Five minutes into his checks, Stark opens his eyes again. “It’s getting worse,” he rasps.

“Yes. Whatever you are making—”

“It’ll be finished soon.” Stark takes several long, slow breaths, gaze fixed on the ceiling. “D’you know how to build a pacemaker?” he asks at last.

Yinsen blinks. “Yes, but—”

“I need drawings for one of those, too.” Stark closes his eyes. A fine shiver runs over his body.

“You should rest.” Yinsen pops the stethoscope out of his ears and moves on to checking the incisions. “I’ll have all three drawings ready when you wake.”

“You can do that in twenty minutes?”

“Two hours at least.”

“Half an hour. I’m almost there.”

“Two hours and no less, Stark.” Yinsen glares at him narrowly. “That was a spontaneous arrhythmic episode. All the others have had immediate causes. Unless I missed you shocking yourself, you’re deteriorating much too fast. I _should_ make you sleep eight hours, under observation.”

Stark squints back petulantly. “Sixty minutes. Glad that’s settled.”

Yinsen just shakes his head and silently vows not to wake Stark up for at least the full two hours.

\---

Once Yinsen _finally_ wakes him up, and don’t think he’s going to forget that, Tony spends the next eighteen hours working. He’ll find out the precise timespan later, with a glance at Yinsen’s watch and a bit of mental math: while those hours are actually passing, he is only tangentially concerned with time. Tony has a project, and he is Working.

He cuts. He solders. He welds, coils, hammers, carves, molds, files, glues, etches, _builds._ The device takes shape under his fingers. It takes real effort to push aside the pain from his damaged chest, more than he usually needs just to ignore his body’s whining, but he works through it anyway. The structure under his magnifiers and his soldering iron is a work of genius, if he does say so himself, and he isn’t going to let the pain distract him from getting it right.

What he’s building is also, a small internal voice reminds him, completely impossible. He shuts that voice up before he can remember that it’s actually half right.

At intervals, Yinsen intrudes on his concentration with medical tools, food, or blankets. Tony doesn’t fight the checkups, eats a little whenever he can spare a moment, and brushes off all suggestions of sleep. He’ll sleep when he’s done. If the doc doesn’t like that, well, Tony would be done a lot faster if he had someone to keep an eye on the glass annealing by the forge, so Yinsen can go do that, yeah?

Yinsen grumbles his way out of the immediate vicinity, and Tony submerges again in his Work.

Finally, finally, it’s complete. The palladium ring is threaded through a dozen stabilizing and amplifying coils, forming the device’s delicate core. He’s got the core nested safely in its casing. The ring, in his mind’s eye, lies overlaid on the real object like one of JARVIS’ holograms. (Dammit. Thinking of JARVIS isn’t helping, either.) The casing is reinforced, evacuated, sealed. Through the lead-glass window on top, he envisions the cold blue light. The connectors are seated, solid, at the end of the flexible cable. He’s hooked them into the power supply for the cave’s lights; it was the easiest way to get the wattage for the bootstrapping.

He draws himself up straight, sitting before his workbench. His hand on the valve switch, smoothly stroking it open, betrays none of the million calculations and plans and misgivings coruscating in his brain. His math is never wrong. This is impossible. He’s _Tony Stark._ (Secretly, he isn’t sure _what_ he expects to happen.)

As the cave fluorescents flicker and fade, the reactor washes him in icy arc-light.

It’s working. He’ll have to check the output immediately. In thirty-two minutes the coolant lines will need to come off. Three gigawatts would overheat the magnet, so they can’t connect it until he builds the new baseplate...

Yinsen moves quietly up beside him, leaning in. The other man breathes out a low, astonished sound. “That doesn’t look like a Jericho missile.”

Time to let him in on the secret. “That’s because it’s a miniaturized arc reactor. I got a big one powering my factory at home.” He taps one finger against the device’s case. It’s faintly warm, thrumming. “This should keep the shrapnel outta my heart.”

“But what could it generate?” Good man. Always know your equipment’s tolerances.

“If my math is right—and it always is—three gigajoules per second.” The reaction’s self-sustaining now. Tony closes the valve switch and their cell brightens.

In Tony’s peripheral vision, Yinsen is trying to keep the astonishment off his face. “That could run your heart for fifty lifetimes.”

“Yeah.” Tony flicks a glance at the doctor. “Or something big for fifteen minutes.”

For a moment they both sit, holding tight to their calm against the impossible glow.

Tony’s head is so full of plans that he misses Yinsen’s first few words: “—very short.” At the engineer’s “huh?”, Yinsen repeats himself: “For something meant to be carried in your pocket, its cables are very short.”

...Time to let him in on the secret.

“I’m not gonna carry it in my pocket.”

“Then how—”

“Said it before. I’m gonna need your help for this.”

\---  
\------  
\---

[TBC]


	4. Redesign

**Summary for the Chapter:**

> _It’s been strangely energizing, collaborating with the engineer. When the pair of them are trading salvos, crashing up against and feeling their way around the conflicts between the reactor’s requirements and those of flesh and bone, the bright spark of creation washes out the cold and shadow of the cave. When Yinsen’s absorbed in the challenge of it, he can almost forget where he is and what he’s making._  
> 
> _Now, though, with the lights dimmed and Stark in repose, he doesn’t have much choice but to think about it._

**Notes for the Chapter:**

> (redesign: the act of revising a plan in light of new information)
> 
> Thank you so much to everyone who's been reading! I've really appreciated the comments and the encouragement. This thing is turning into an epic on me. For all that I've pretty much failed at my one-chapter-per-week goal, I promise that I'm writing steadily: I _will_ finish Revision. At the moment it's looking to finish at around eight or nine chapters, and it'll only get longer.
> 
> A belated shout-out, too, to my fantastic beta! [fledisthatmusic](http://archiveofourown.org/users/fledisthatmusic/pseuds/fledisthatmusic) has been immeasurably helpful through all this. Writing buddy, you are awesome, and I owe you more than one. Thanks, too, to [sara_wolfe](http://archiveofourown.org/users/sara_wolfe/pseuds/sara_wolfe) and [notyour-sidekick](http://notyour-sidekick.tumblr.com/), who have also betaed various chapters. I couldn't do this without you guys!

“This is ridiculous. I won’t do it.”

Tony sets his jaw. He was afraid of this. In the two or three minutes since he unrolled his plans for an arc-reactor socket and handed them to Yinsen, the doctor’s olive skin has been slowly paling. His eyes dart all over the page, taking in the details of what Tony’s asking him to do, and his expression is positively sickened.

Yinsen looks Tony in the eye and tries to shove the plans back into his hand. Tony leans back a few degrees, palms in the air. “Wanna at least tell me what I did wrong? I was pretty sure that thing would work, you know.”

Yinsen’s fingers clench. “It’d _work_ — For God’s sake, Stark!” He tosses the plans down on the workbench and shoves himself to his feet, stalking a few steps away. “You know very well that I cannot advise you on the engineering, but medically... It’s ridiculous,” he says again.

Tony waves one hand in a circle, the universal “go on” sign. “Yeah...?”

“You really want the details?” Yinsen snorts. “All right. This would _kill_ you, you idiot, and even if it did not, it wouldn’t work as a pacemaker—these electrodes are nowhere near correctly placed. You can’t rely on the sinoatrial node alone in a case like yours. Not to mention that embedding the magnet that deeply would pull at least two pieces of shrapnel right through the pericardium.

“And all that would be completely irrelevant when the entire device would be compressing your lungs and ascending aorta, compromising your sternum, and _replacing the entire upper half of your heart._ Your body would never heal around this thing, Stark. You’d die on the table.” He scrubs a hand roughly back over his scalp.

“See, this is why I brought it to you,” Tony says. It gets him a glare. “No, seriously. If it’s too deep, okay, there are ways I can make the socket shallower. And if the electrodes are placed wrong, you tell me where they _should_ go, and I’ll put ‘em there. We’ll make it work. Yeah?”

“ _No,_ “ Yinsen snaps. He points to the workbench beside them, where a convenient cardboard box shields the cameras from the arc reactor’s glow. “Nothing you do to this design will change the fact that you are trying to embed a device the size of my fist in your thorax. Do you have any idea what this would _do_ to you? Even if you survived, you wouldn’t be able to move your arms. You wouldn’t be able to _breathe._ “ He tries to glare balefully, but the incredulous anguish under it kind of ruins the effect. “You’re asking me to mutilate you, Stark!”

Tony clamps his mouth shut. If he lets himself open it right now, he’s not going to be responsible for what comes out. _Do you think I’m stupid?_ , maybe, or _Any worse than you already did?_ —because the magnet’s a hot, aching weight under his shirt, and what does Yinsen think that is, a fashion accessory?

He glances away. “I know,” he manages, when he’s got control of his voice again. “Still. Got any better ideas?”

\---

Yinsen doesn’t.

He stares at Stark, mouth hanging stupidly half-open, and realizes that he really doesn’t. The battery is going to run out, and Raza has already made it clear that there will be no others. If they replace it with the arc reactor, Raza will see the glowing work of technical genius dangling from Stark’s chest, and Yinsen is afraid the man will decide he’d rather have that than a Jericho missile. If they want to keep the reactor, they’ll have to make it seem impossible to remove...

Stark must be able to read his expression, because the engineer gives him a thin-lipped smile. “Didn’t think so. Besides, I’ve got you to fix it. Between the two of us, we oughtta be able to build something that won’t kill me, right?”

This is insane. He can’t possibly be considering it. It’s just not possible, not here, operating in a _cave_...

Is there any other option?

Yinsen feels his shoulders drop, but he moves back to the bench and picks up the plans again. “This is a terrible idea, Stark,” he mutters.

The corner of Stark’s mouth twitches upwards. “Didn’t you ever watch Letterman? I’m the _king_ of terrible ideas.”

Yinsen snorts, spreading the pages out over the workbench. For a few minutes, he peruses them, trying to decide which of the problems to tackle first. He picks up a pencil and starts marking, lightly, as he enumerates the issues. “We’re not going to be able to fix this instantly, you know.” He circles the SA electrodes, scribbling a note beside them to remind Stark of their insufficiency. Next... hmm, that would cause immediate pleuritis... He starts marking up the outside of the reactor casing.

Stark moves up to peer over his shoulder. “‘Course not. There’s a lot to tackle.” He winces a little at the abundance of pencil-marks. “In my defense, if I were doing this at home, I’d have been able to do my research first.”

“If you were at home, none of this would be a problem,” Yinsen points out dryly.

He can actually feel the man flinch. “Yeah, well.”

“Given the circumstances, though, it’s surprisingly well-informed,” Yinsen offers. He taps the drawing with his pencil, pointing out the formulae for the coating Stark has planned to apply to the device’s walls and work into its sealants. “Most people wouldn’t have considered the possibility of immune rejection. Even fewer would think to make the anti-rejection coatings so long-lasting. With these, you wouldn’t need immunosuppressants, even fifty years afterwards.” He looks up at Stark. “For all its flaws, this would be very stable as a permanent implant.”

The man looks away for a moment, his eyes shuttered and his throat working. “Yeah, well, genius work of engineering,” he manages, and then pulls on a sly grin. “It damn well better last the whole fifty lifetimes, huh?”

Yinsen rolls his eyes. “Oh, go away. Get some rest. Make some dinner when you wake. I'll tell you when I’ve finished marking this up.”

\---

“Dinner’s on.” Tony pokes Yinsen’s shoulder, nudging one of their chipped bowls onto the workbench next to him. “Surprise! Rice and beans.”

Doc looks up. “Oh. Thank you.” He trades his pencil for the bowl, stands up, and stretches a little before digging in without further comment.

Huh. That’s different. People are usually a lot more surprised when Tony cooks without setting anything on fire. He was all ready to defend himself, tell Yinsen that it’s just chemistry with a bigger margin of error, and that it may not exactly be ritzy but he can still make rice and beans at least _edible_... but the guy didn’t really even notice. He’s not quite sure what to make of that.

Eh, whatever. It means he can get a look at Doc’s work sooner. He reaches out for the plans... only to jolt back with an indignant squawk (okay, not just indignation, his ribs don’t like it when he moves that fast) when Yinsen’s hand slaps down on the pages. “Not until you’ve eaten.”

Tony puts on his best expression of wounded innocence. “Doc!”

Yinsen just raises an eyebrow and points with his spoon to the other bowl.

“This is blackmail,” Tony grumbles, but he goes. Dinner will be over quickly enough, at any rate: the Ten Rings are feeding him and Yinsen enough to keep them going, but the rations aren’t exactly sumptuous.

Once he’s washed the stuff down with a tin cup of water and put his bowl by the fireplace to dry, Tony heads back over to the workbench, fingers wiggling in anticipation. “Let’s see it.”

Yinsen notes Tony’s empty bowl before setting his own aside—Tony would be insulted if that was any less justified—and handing over the drawings. “Here.”

Tony spreads them out and leans over to look. The casing is considerably shallower than before, and he’ll need to rework the connectors and the magnet accordingly... actually, yeah, it looks like Yinsen’s pretty much left the decisions about the housing’s insides up to Tony. Okay. The outside, though... there’s a lot more detail there, and it’s all annotated in Yinsen’s angular handwriting, explaining in no uncertain terms why each change is necessary.

He settles down to examine the biggest changes more closely. Where Tony had the casing bolted straight to the sternum and ribs, Yinsen has changed the rib connectors to flexible expansion joints; his annotations specify exactly how far they’ll need to be able to expand in order to accommodate normal breathing. He’s added delicate fluting to the rim around the lip of the thing, too, improving the attachment points for the displaced pectoral muscles. He’s made notes on the best sealants to use, and how they might be able to get them down here in the cave. Most amazing of all, though, is what Yinsen has drawn instead of the single pair of pacemaker electrodes Tony’d planned: a veritable web of fine wires spreading from the device’s base to touch the heart beneath.

Tony traces these with something like awe. They don’t just reach the heart—well, a handful of them do, at the failing natural pacemakers, but many others fan out deeper into the chest. They connect with the major arteries and veins, the nerves, the lungs. He doesn’t even recognize what half of them are doing: the electrodes he understands, but these three are tipped in pressure sensors, and that’s... a chemoreceptor? Oh, that is _sweet_ , he hasn’t even seen that design before, does Yinsen want him to miniaturize it on the fly? The ones coiled around the bronchi seem to be measuring diameter, and he can already see a few ways to improve the sensor, but _why_ are they doing that?

He flips to the next sheet, hungry for details, and just... stops. “Yinsen? Is this what I think it is?”

“I don’t know,” Yinsen says dryly. “What do you think it is?”

“I think it might be the electrical systems of the human heart, drawn out as a circuit diagram.”

“Then it is what you think it is.” The doctor grimaces. “It’s crude, though. I could only do so much from memory.”

“Sure, okay.” Tony honestly doesn’t care that much, not in the face of Yinsen having taken the time to translate this into Tony’s language. It makes _sense_ , laid out like this...

...and the more sense he makes of the heart, the more he appreciates Yinsen’s design.

Ten minutes later, or maybe an hour, he surfaces from the drawings. There may or may not be a pretty stupid grin plastered on his face. “Jesus, Yinsen. Where have you been all my life?” Before the doc can get snippy about that, he barrels on: “This is gorgeous. No, seriously, amazing. I mean, yeah, I’m still gonna have to go in and redo the reactor connections and the pacer chips and everything inside the casing, and I can improve on a lot of the microsensors, but what you just did with the pacemaker? You’ve gotta write a paper, it’ll get you a fucking Nobel.”

Yinsen’s eyes are very round behind his glasses, but a tiny frown creases his brow. “Thank you,” he offers, hesitantly.

“I’m serious. You just improved on my work by _miles,_ and I am really not used to saying that.” For the first time in weeks, he isn’t having to force his smile. “This thing is gonna be beautiful,” he adds, and on an impulse, sticks out his hand.

Yinsen hesitates for an instant, that tiny frown deepening. Then it smooths back out, and he takes Tony’s hand. His face is still solemn, but his grip is warm, dry, and very strong.

\---

It’s late, Yinsen thinks. Time is difficult to track in the sunless cave, but even under the mountain, he thinks the air is cooler and moister at night. The guards turn the lights off at intervals, but he doesn’t trust them to stay truly synchronized to the days.

Right now, regardless, it feels late. Their cell is dark and cold. Stark is an indistinct mass huddled under the blanket on his cot; Yinsen can just make out the slow rise and fall of his breathing. The man finally went to bed half an hour ago, when he could no longer pretend that he didn’t need it. Yinsen had made sure to stay within arm’s reach as Stark shuffled over to the cot; the man was trembling as if the only thing still holding his bones together was his faltering will, and Yinsen hadn’t wanted to risk letting him fall and break something. Now he’s lying half-curled on the cot, caught between the instinct to curl around his chest and the complaint from his ribs when he tries. He’s breathing unevenly, pained even in his sleep.

Yinsen looks down at the blueprints, spread out on the table before him. It’s too dark to work now, but he can trace most of it from memory: he and Stark have been working on the design for nearly thirteen hours. It’s been strangely energizing, collaborating with the engineer. When the pair of them are trading salvos, crashing up against and feeling their way around the conflicts between the reactor’s requirements and those of flesh and bone, the bright spark of creation washes out the cold and shadow of the cave. When Yinsen’s absorbed in the challenge of it, he can almost forget where he is and what he’s making.

Now, though, with the lights dimmed and Stark in repose, he doesn’t have much choice but to think about it.

He brackets the depth of the socket with his fingers, checking it against the drawing’s scale. They’ve made it much shallower than Stark’s original, lethal plan, but still... It will sit more than three inches deep in Stark’s chest, the baseplate all but resting against his heart. Yinsen will have to saw out most of the man’s sternum, excise parts of his _lungs._ He’ll never take a full breath again. Even getting to the point of worrying about his long-term lung capacity will be an ordeal. In a modern hospital, the operation would be difficult and Stark’s recovery prolonged and painful; here, it will be hell. 

Yinsen scrubs his hands over his face. Why is he even considering this? He should have refused outright, made Stark see it for the horror that it is. It makes mockery of any claim he’s ever had on medical ethics. What kind of butcher is he, that he’s helping to plan it?

What will it make him if he carries it out?

What will it make him if he refuses?

Yinsen rolls the plans up and pushes them away. If he refuses, Stark will die—either swiftly, when Raza loses patience, or slowly and horribly, when the battery runs out. He can’t just stand by, offering laughably useless palliative care as the shrapnel rips his patient apart. He’s damned for butchery if he acts and for Stark’s death if he doesn’t.

If he throws up his hands and just watches Stark’s final agonies, though, he will be giving up. Even in the privacy of his own heart, he will no longer be able to call himself a doctor.

...No.

Everything else that ever mattered to him is dead. He _will not_ throw his vocation on the pyre.

Yinsen shoves himself to his feet and pads across to the coal burner. He picks up the poker and jabs, making the fading embers flare. God help him, he will do it: he’ll operate. He’ll help Stark break his own body down for parts.

If he’s very good, and very lucky, they may even be able to build a whole person from what's left.

\---  
\------  
\---

[TBC]


	5. Proximal Causes

**Summary for the Chapter:**

> _He's been staving off the panic for days, mostly by depersonalizing everything: it was always_ the _socket,_ the _heart,_ the _patient. Never Tony. Never himself. If he allows himself to think about it that way, think of it as cutting into_ Tony's _chest, jabbing wires into_ Tony's _heart, bolting the socket into_ Tony's _body—_

**Notes for the Chapter:**

> (proximal causes: the events most immediately responsible for an outcome)

"I'm telling you, that's not gonna work. The reservoir'd leak like the Titanic after a week in Baffin Bay. If you want to keep it sterile, we'll have to... take apart... one of the... Sparhawk stabilizers... A little more to the left... no, your left!"

"Sorry. Farther inward? And I thought you said the Sparhawk stabilizers were Kevlar-coated."

"They are. In and up... Okay, clip it."

"Mm-hm... There, how's that? Between the solvent and that combination of catalysts, we'd risk beginning to break the Kevlar down, and you don't want _those_ monomers in the mix. The final product would be toxic."

"Worse than the plasmic discharge?" Tony selects the smallest pair of calipers and measures the protruding few millimeters of fine plastic tubing. Just right. "Yeah, that's good. Grab the next one."

Yinsen turns to the other side of the workbench, selecting the next four hair-thin wires from the rows he helped Tony lay out an hour ago. "Much worse. You'd have cyanogens leaching into your chest."

"Right," Tony mutters. Cyanide poisoning: not his cup of tea. Dammit. "Okay, twist those four and thread ‘em through—"

A metallic clangor scatters his thoughts. Barking voices echo outside their door.

The wires are instantly forgotten. Tony and Yinsen both jump to their feet; Tony grabs the battery, which really hurts to carry while trying to put his hands behind his head, but he's not going to put it down _now_ —not with the doors creaking open and men in ragged green flooding in, especially not when the big beardy slug's among them, and sure as _hell_ not when Beardy's wearing _that_ look. The guy's glowering so hard that his caterpillar-thick eyebrows have knitted into one solid line. It could be funny, except that that was the last look Tony saw before too many of his rounds with That Barrel.

Tony's stomach turns upside-down, then contracts down to a geometric point. Beardy can't have figured them out already. Right?

Well, it's out of his hands for now. He doesn't have to understand the words to see that Beardy's just dripping suspicion, but the little bit of Dari that Tony's picked up isn't enough to tell him what the guy's suspicious about. He's got a pretty good guess, but interrupting probably wouldn't help. Yinsen will bring him into the conversation when he can...

Yinsen answers Beardy without stopping to translate. Tony's heart lurches, skips, starts racing: he's out of the loop. Shit. Why is he out of the loop? He can help this time—if he'd skipped the damn Italian classes and studied the _right_ language, he'd be defending _himself,_ like he should be—so why is Yinsen leaving him back? He can't just stand here!

 _If I didn't already trust you, Doc, we would be having_ words _right about now._

\---

"I swear to you, this is necessary. It's as I said three days ago: Stark needs a pacemaker. If you want him to live long enough to build the missile, we must build this first," Yinsen explains.

Bakaar's glower doesn't waver. He points one slab-like hand at the half-finished arc socket; Yinsen follows the finger involuntarily. "That is no pacemaker."

Yinsen's hands, still locked behind his head, are beginning to sweat. He supposes it was too much to hope that even a man of Bakaar's phenomenal medical ignorance could mistake their work for a pacemaker: the open titanium cylinder, trailing spiderwebs of tiny wires that vanish into unfinished silicone conduits, does not look like anything meant for implantation in a human body. "It's a pacemaker built from missile parts," he hazards. "It will save his life, but it's... not elegant."

Bakaar snorts. Evidently, he does not think very much of elegance. He seems to be accepting Yinsen's explanation, though. He moves up beside Yinsen, to the workbench where the arc socket sits, and bends close in to examine it. Big, blunt fingers trace the circular rim. "How long will it give him?"

There is probably a wrong answer to this question. Yinsen wishes he knew what it was. "Long enough, I am sure."

The evasion gets him a sharp look. "How long?"

"M-months. Years. A good pacemaker can extend a patient's life for decades."

"What you're building, it's not good?"

By all that's holy, he is glad not to be holding a scalpel right now. His incisions would look like something done with pinking shears. "The device—it will _work,_ but it's untested, it's made from scraps. And, and the infirmary here is adequate, but this is major surgery—"

Now Bakaar rounds on him, looming like an angry bear. "The infirmary? No. You will operate here, or not at all."

"No!" The word is out of his mouth before he can regret it. Bakaar does not take well to being contradicted, he knows, but he can't operate here! "No, I need those facilities. You don't understand—this is a highly invasive procedure. Without sterile technique and life support, it _will_ kill him. Medical facilities, the right tools, the drugs, I need them all or he'll die on the table."

Bakaar's look only grows darker. Now Yinsen knows he's babbling, but he can't just leave it. "Please. I must do this, and do it right. It's his life. He can't build the missile if he dies; you know that, or I wouldn't be here at all—"

"Silence." Bakaar holds up one hand; Yinsen's mouth snaps shut. For an interminable moment, they stare at each other.

Then the guerilla lowers his hand. "All right." The glower hasn't faltered. "Write a list of what you'll need and give it to me tonight. You'll have your infirmary. See that he lives." _If he dies, you die:_ it wouldn't need to be said, even if it did matter. If Stark dies, Yinsen will have little reason left for living anyway.

Yinsen nods. "Thank you," he manages.

Abu Bakaar turns away. "Get back to work," he growls, lumbering out of the cell. The rest of the Rings follow him, until the door booms shut and the prisoners are alone once more.

The moment the door slams, Stark rounds on Yinsen. "What the hell was that?" he demands, his voice rising with barely-contained hysteria. His face is gray again and he's shaking all over.

Yinsen's hands aren't much steadier, but he has enough calm left to take Stark's wrist. The pulse is much weaker than he'd like, and far too fast; he directs the man to his stool at the workbench. "Sit. He wanted to know what we're doing."

"What'd you tell him?" Stark obeys, setting the battery on the bench beside him and leaning over the worktop without ever breaking his wide-eyed stare.

"It's a pacemaker, it'll save your life, we absolutely have to put it in, and we absolutely have to have decent facilities to do it." The immediacy of patient care is leaching the tremors from Yinsen's own limbs; Stark's are not following suit, more's the pity. He's not getting worse, though; time and calm may be enough. "He wasn't convinced at first."

"He is now, right?"

"Yes. I managed that much." Stark lets out a soft sigh at that, and his pulse finally begins to settle. Yinsen still leans over to grab the nearest blanket and drape it around his shoulders. "He wants me to make a list of materials by tonight."

Stark looks away from Yinsen, staring down instead at the arc socket whose wires lie splayed out across the table. It isn't ready. Stark had said he planned to have it done by tomorrow night, but their deadline has been moved up. Yinsen hopes desperately that the man can work under pressure.

When Stark finally looks up from the device, Yinsen can _see_ the calculations behind his eyes. "I guess we better get working, then, huh?"

\---

Tony hasn't slept. It's been too long, he knows, and he'll need all his strength for tomorrow—okay, by now it's today—but he can't. There's too much going on in his head for him to seriously consider sleeping. All night, he's just been staring at the shadowed stone ceiling and thinking.

So here it is, something like six in the morning on the big day, and he hasn't slept. He's going under in about four hours, but that probably won't count. He closes his eyes, trying to relax, and runs their preparations through his head for the thousandth time.

The socket itself is finished; he and Yinsen put the finishing touches on the thing just a few hours after the doctor had to deliver his materials list. Having their deadline moved up like that was actually unexpectedly calming. Tony's had worse clients and shorter notice than this: it was just like one of the all-nighters he keeps having to pull for that godawful Pret-Oberman contract.

They have the necessary materials; a suspiciously short while after Yinsen handed over his list, Beardy's lackeys delivered several crates of haphazardly-sorted medical supplies to the cave infirmary. They refused to say where it all came from, though. The sons of bitches might just have had it all in storage—Yinsen's apparently been their prisoner for some time, so they must have kept some equipment around for him to treat their various wounds—but they're equally likely to have gone out and knocked over some hospital. Tony's added that to his list of Reasons the Ten Rings Need to Go Down.

The theater's been prepared; as soon as the materials arrived, Beardy grudgingly allowed Yinsen most of a day in the infirmary to sort, set up, and sterilize his various equipment. The doctor had come back looking weirdly serene, even with the guard's rifle jabbing him forward into the cell. Maybe prepping for surgery is as comfortingly normal for him as last-minute engineering is for Tony.

Surgery. Tony can't help the shiver that wracks him at the thought. _Dammit, Stark, keep it together!_ He's been staving off the panic for days, mostly by depersonalizing everything: it was always _the_ socket, _the_ heart, _the_ patient. Never Tony. Never himself. If he allows himself to think about it that way, think of it as cutting into _Tony's_ chest, jabbing wires into _Tony's_ heart, bolting the socket into _Tony's_ body—

he knows exactly what it will feel like, fingers under his ribs, knives digging for the barbs, the magnet grinding at his bones, and he wailed and thrashed and they _held him down—_

Tony blinks. He's sitting bolt upright on his cot, shaking violently, with both arms wrapped around his chest as if to hold his insides in. He's panting. Sweat drips down his back.

"Stark?"

Yinsen's awake. Shit. "Yeah?" Tony croaks.

There's a soft sound of fumbling, and then the doctor's glasses glint dimly in the near-darkness. "Are you all right?"

Tony doesn't want to dignify that with a response. A few hours before fucking terrifying, life-changing surgery, in a _cave,_ unconscious (please, God) in the hands of the terrorists who blew him up and drowned him and the guy who cut him open? Oh, he's just _peachy,_ thanks for asking! "M'fine," he says instead.

For a moment, the only sound is Tony's still-harsh breathing. Finally: "You remember, don't you." It isn't a question.

Tony figures his silence is probably answer enough.

The glasses-glint tilts downward: Yinsen has bowed his head. "You woke at a terrible moment," the doctor murmurs. "I couldn't stop working, or you'd have bled out. None of the men would help me sedate you. I'm so sorry."

Tony's vision seems to tunnel down, locking on the dim flash off the glasses. Distantly, he is aware that his fingers are clenching in his shirt. "You're _sorry?"_ he snaps.

"Yes."

"Fuck that," Tony snarls. His heart pounds in his ears. "I don't give a shit how it happened, _doc,_ what matters is that I fucking _woke up_ with your goddamn hands in my chest!" He's panting now, biting out the words between gasps for air. "I couldn't even pass out! And, and for what, so I could wake up to _this?"_ Tony claws at his own chest, trying mindlessly to crush down his galloping heart. It batters his ribs from the inside and his arms squeeze them from above, bones still grinding, and it _hurts_ like he's on the table again—

"I'm sorry." The shadow of Yinsen's shoulders stoops even deeper. "You'd have died. I couldn't—"

"Yeah, well, maybe you should have _let_ me!"

Yinsen's entire silhouette flinches as if Tony's punched him, but the man comes right back to bolt up off the cot, and then he's right there beside Tony. This close, Tony can see more of his face: wide eyes, a grimace of anguish or guilt. His hands grip the edge of the bed. "Do you really believe that?"

His tone is... strange. Not challenging, not demanding. Pleading. It's actually a question.

 _"Stark._ Do you? Do you really wish I had let you die?"

The hands on the edge of the cot are shaking.

Tony's arms loosen. If Yinsen had let him die on the table, this hell would have ended. No more pain, not for him. But he'd never even have had a chance to see Pepper, Rhodey, or Obie again. He'd never have miniaturized the arc. He'd never have planned to take the Ten Rings down. He'd never have had a chance to _change._

Down here in this cave, he's met his legacy—blood and ashes—and resolved to change it, to get out of here and build something better. If he'd died on the table, he never even would have known. He never would have been anything more than the Merchant of Death.

The thought makes him shudder and let his arms drop. He buries his face in his hands. "No."

\---

Yinsen's mind is a roaring blank, all thoughts overwritten with his desperate relief. Stark does not regret surviving; Yinsen did not put him through another torture for nothing. For a very long moment the cave is quiet but for the distant dripping, Stark's ragged breaths, and the pulse in Yinsen's ears.

He swallows a few times before deciding he can trust his voice. "It won't happen this time," he promises, and is distantly surprised by how steady he sounds.

Stark scoffs.

"Failing anything unforeseen, of course. It's highly unlikely, though. Once I told Bakaar that your movements would kill you if you woke again, he brought us enough ether and ketamine to keep a horse down for three days."

The silhouette on the cot shifts. There's another long pause, but then: "Okay."

Yinsen nods. Closes his eyes. Breathes. "All right."

Stark lets out a sudden, explosive sigh. The cot creaks: he's lying back down. "You better not fucking OD me, though. I'm not a horse." He's trying to smile; Yinsen can hear it in his tone, though it isn't working very well. "And if something does happen, just..." He trails off, throat clicking as he swallows hard.

Yinsen straightens, frowning. "Stark?"

Another sigh. Stark shifts on the cot. "Just don't fuck it up, okay?"

Yinsen is wondering how to reply to _that_ when the lights come up. It's morning.

Time to go.

\---

The infirmary's ceiling is rough-hewn stone. Tony examines it in minute detail. The longer he can spend cataloguing the precise fracture lines and shades of gray, the longer he can keep his calm: when he's thinking about what tools were used to carve this room out of the rock, he isn't thinking about the chill of the operating table on his back, the rhythmic monotone of the heart monitor, the pinch of the IVs in his hand and arm, the mutter of the scrubbed-up guards in the corner, or the fact that Yinsen will be putting him under sometime in the next few minutes.

For a while there, he'd been pushing back the fear by helping Yinsen prep his equipment: however alien its purpose, the gear is all still machinery, and he can check power connections in his sleep. Once the doctor finished preparing his equipment and moved on to preparing his patient, though, Tony could no longer be the engineer. Hence his intent study of the ceiling.

God, he hates this. He can deal with being scared; that's not the problem. He's got plenty to be scared _of_ , between the memory of his last surgery _(stop thinking about it!),_ spending who knows how long unconscious in easy reach of the Ten Rings, and having to lie utterly passive while Yinsen remodels his innards. What's killing him is the goddamn paradox of it. He _hates_ having to give up all agency for so long—if something goes wrong, he'll never even know it—but the mere thought of waking up before it's time is enough to make the heart monitor start galloping.

He just doesn't want to die helpless. Is that too much to ask?

"Ready, Stark?"

The surgeon's voice is gentle, but Tony still jumps. He makes himself meet Yinsen's eye, forcing a suggestive eyebrow waggle, and doesn't let his gaze stray to the bottle and gauze in the doctor's hands. "For you, doc? _Any_ time."

Yinsen sees right through him, of course, but he only tilts his head. Beardy's watching them, looming and ursine even through the little glass window in the infirmary door; this is a lousy time for comfort. "Then breathe deeply, and count backwards from ten."

Tony closes his eyes, and the gauze wraps him in sickly sweetness. He fills his lungs for the last time. Ten... nine... eight...

As the void's cool fingers draw him gently away from the world, awareness recedes to a distant spark, and thought dissolves like smoke, Tony offers up a final desperate prayer.

_Please, Yinsen. Don't fuck this up._

\---  
\------  
\---

[TBC] 


	6. Revision

**Summary for the Chapter:**

> _His consciousness ebbs and flows with the air moving in and out of him, now blotted out in the screech of grinding bone, now clearer for a moment when his ribs fall still. In the quiet between breaths, slivers of awareness slip through. The quiver of muscles trying to draw taut against his need to swallow, or to gag. Something heavy and alien driven deep into his chest, radiating awful chill right into his core._

**Notes for the Chapter:**

> (revision surgery: a procedure performed to replace a failed implant, or to correct undesirable sequelae from a previous operation)
> 
> So sorry for the delay! This chapter and the next (i.e. what I originally planned for chapter 5, before chapter 4 started sprawling) have been very difficult to write. Writer's block sucks. There will also be a bit of a break over the holidays; I'm going home for Christmas, and there won't be much time to write. I will finish this thing, though, even if I don't publish again until next year. So happy holidays, everyone! I'll see you again soon.
> 
> This chapter was betaed extensively by both the flawless [fledisthatmusic](http://archiveofourown.org/users/fledisthatmusic/pseuds/fledisthatmusic) and the expert [MountainRose](http://archiveofourown.org/users/MountainRose/pseuds/MountainRose). I love you guys.
> 
>  **Warning for this chapter:** Surgery. Skip the first section if this is a trigger.

Stark’s heart is still beating.

For hours now, Yinsen has worked to its rhythm. The shrill ostinato of the heart monitor had paced his initial incisions and the removal of the old magnet. It had parceled out the seconds as he marked the bone exposed beneath, audible even over the grind of the saw that he used to cut a circle out of Stark’s sternum and ribs. Underneath, the heart itself had pulsed slow and faintly uneven; he'd had to time every incision against it, working _oh_ -so-carefully around the constant motion as he removed the thymus and the medial lobes of both lungs. More than once, as he probed deeper into the chest cavity to place each of the pacemaker's delicate sensors and electrodes, the heart had stuttered and heaved; each time, he froze his work to monitor it, fearing again that the shock of surgery had triggered a fatal arrhythmia, but each time it had stabilized on its own.

There's a hole in Stark's chest eight centimeters wide now, a perfectly cylindrical cavity right down to the surface of his heart. At its edges, the cut ends of bone are capped off in shining steel: the rib ends of each expansion joint. At the bottom rests the connector for the pacemaker, which gathers up the many wires in readiness to meet the reactor housing.

Yinsen looks up from his work to the monitors and equipment keeping his patient alive. Heart rate, blood pressure, oxygen saturation... yes, the patient is stable enough. Time to attach the housing.

The metal cylinder slides into Stark's chest with a wet hiss of displaced air, then a solid _k-klick_ as the rib joints connect. When the ventilator pushes the next breath into the patient's lungs, Yinsen can see the joints flex. He tests their solidity with a few careful presses and tugs; once assured that they'll last, he coats them safely with the anti-rejection sealant. The pacemaker's connector met the reactor on its way down, so Yinsen only needs to ensure that it's seated properly before placing another generous coat of sealant.

Now, the moment of truth. The implant is in place, but does it work? He takes one steadying breath, then plugs in the leads from the car battery.

The heart monitor's rhythm smoothes out to a perfectly steady beat.

Yinsen allows himself one small, relieved smile in the privacy of his surgical mask. The pacemaker works. There are more diagnostics to be done, of course—he must ensure that it will _keep_ working—but on the face of it, his and Stark's mad invention is a success.

He bends back to his work. Diagnostics, final cleanup, closing Stark's chest back up around the new intrusion—he is far from finished. The smile fades. As great an accomplishment as it is to implant this thing successfully, it isn't even half the battle. Stark has a long and difficult recovery ahead. Yinsen steels himself to see it through.

\---

Everything hurts.

When Tony first surfaces from the mire of unconsciousness, he’s aware of nothing else. He’s a formless mass of aching, burning pain. A vague sense of self. It _hurts_... He sinks back down again.

The second time, there is shape to the pain. Limbs. Head. Body. It’s worst at his core: a massive barb through the center of him, dragging him out of the dark like a hooked fish. He tries to gasp, to whimper, but there's no sound: it's muffled by something buried in his throat, a weight so awful that he can feel it through the pain. He chokes on the invader, gags—the spasm rips through his chest, shatters him—the fragments are smoke on the wind.

The third time, he manages to pull a few scraps of thought together. It’s enough that when the thing in his throat registers, he’s coherent enough to try not to fight it. Only by dragging all his tattered concentration together does he manage to keep still, and then only after several helpless swallows that burn all the way down. His hand still lifts involuntarily, trying to reach for his mouth, but the motion rips such a jolt of agony down the middle of his chest that he freezes. Staying still doesn’t help the relentless, stabbing pain in his chest, but at least it doesn’t make it worse. That’s no real comfort.

His consciousness ebbs and flows with the air moving in and out of him, now blotted out in the screech of grinding bone, now clearer for a moment when his ribs fall still. In the quiet between breaths, slivers of awareness slip through. The quiver of muscles trying to draw taut against his need to swallow, or to gag. Something heavy and alien driven deep into his chest, radiating awful chill right into his core. Somewhere above him, a distant muffled hum.

The hum grows louder with each breath. Closer. Now and then, it resolves into something vaguely familiar, like a radio tuned back and forth across a recognizable station.

Words. “...awake... hear me... if you...”

It takes a very long time for his brain, scrambled under the raw rhythm of the pain, to assign the voice a name. _Yinsen._

“Open your eyes, Stark.”

His eyelids flutter. Light.

“That’s it. All the way, if you can.”

Bright, _stabbing_ light. He slams his eyes shut again, his head flinching away. The motion makes the weight down his throat shift faintly, and it takes all his willpower to keep from gagging.

When he can think anything beyond _don’t choke don’t choke don’t choke,_ he registers a touch, warm on his cheek. “Easy, Stark. You’re doing well. Can you open your eyes?”

He squeezes them tighter shut. Above him, a soft sigh. “All right. That’s all right. Just rest.”

Rest. He takes stock of himself—fighting not to choke, trembling with fatigue and the cold at his core, greying out on the pain of another inrushing breath—and wants to laugh. His fingernails drag over cool canvas, and even that slight motion tugs a blade lightly down the center of his chest.

A warm hand closes over his. “Can you squeeze my hand?” He tries. “Good. Can you tap out the first five prime numbers for me?”

...what? Why does he want... Shit, he hurts too much to care. His index finger taps against what must be the back of Yinsen’s hand. Tap. Tap tap. Tap tap tap—one, two, three, five, seven, tapping each number in the space between breaths. By the time he’s done, he’s reduced to faint twitches against the skin.

“That’s very good. Okay. How about pi? Tap out every other digit of pi.”

What does Yinsen _want_ with him? He trembles for a moment, finding the strength to move again. Three, four, five, two, five—by the fifth digit, even he can barely feel the twitches.

“All right, that’s good, that’s enough.” Yinsen’s hand squeezes his, strong and gentle. He falls gratefully still, screwing his eyes shut against the next breath. When his hearing comes back from that, the doctor’s in midsentence: “—was successful. The housing and the pacemaker are in place, and your heart rhythm’s stabilizing nicely.”

It takes much too long for Tony to understand what that means, and even longer for the news to sink in. When it does, the flare of relief is faint and distant, but it’s there all the same. Tony marshals his strength and makes his fingers wrap more closely around Yinsen’s hand..

Warmth touches his forehead. “Yes, it’s a relief. Now, Stark, I need to know how you’re feeling. One squeeze for yes, two for no. Understand?”

He manages a feeble squeeze.

“Does it hurt anywhere specific, other than your chest?”

Anywhere? He hurts _everywhere._ Tony’s free hand scrapes weakly at the canvas. He’s so goddamn weak, he can’t move without choking, his chest is _reamed open_ —Jesus, what kind of question is that?

Probably an important one.

 _Fuck._ He fights back another choke, forces his quivering body to lie still. Does he...? His chest, of course (God, his chest), and his throat, and a bone-deep ache all over... but nothing more localized than that. He squeezes once, twice.

“That’s good. Any numbness or tingling?”

He can only wish. Two squeezes.

“All right. Last question. On a scale of one to ten, ten is the worst, how bad is the pain?”

Tap, tap, tap, tap tap tap tap tap-tap-taptaptaptap—

The warm hands close around his again, stilling his frantic SOS. “All right, Stark. All right. Relax. I’ll get you something for it, just hold on a moment.”

His hand is left to tremble in the cold air. He curls it against the rough canvas and just tries not to choke. An eternity later, there’s a rush of cold in the crook of his arm, spreading a paradoxically warm relief through his veins. Soft clouds spread out to cover him and he can’t think, doesn’t want to, because the pain’s draining away with his thoughts and he can just sink back into it. He can drift.

He’s drifting.

\---

As the tension bleeds from Stark’s muscles, Yinsen lets out a long, slow sigh. His patient has a long way to go yet. Stark was conscious enough to answer questions, and to stop himself fighting the ventilator; at least there’s no evidence of stroke or any wandering blood clots. He’s very weak, though, and clearly in tremendous pain. They both knew that was inevitable, but that doesn’t make it easier even to watch.

Yinsen sighs again and bends to check the chest tubes. Stark will need the ventilator for several more days, until he heals enough to risk trying to breathe on his own. In the meantime, the painkillers will shield him from the worst of it; since respiratory depression isn’t an issue, Yinsen can use enough morphine to keep him well sedated. Stark won’t truly wake again for days.

In the meantime, Yinsen keeps vigil. He stays by Stark’s cot day and night, monitoring his vitals, keeping the endotracheal tube clear and the chest tubes clean, changing the IV bag. He maintains the flow of morphine and antibiotics, and sends up a quiet prayer of thanks each time he changes the dressings to find no sign of infection. He packs the gaping, titanium-lined hole in his patient’s chest with gauze; there’s no drainage there to absorb, but the bare metal will pour Stark’s body heat uselessly into the cold cave air if it’s not protected. (If it also saves him from constantly confronting what he’s done to his patient... well, that’s a side benefit.)

There are no more cardiac episodes. Stark’s heart thrums slow and steady to the pacemaker’s rhythm.

Then, on the third morning, Stark spikes a fever. Yinsen returns from making breakfast to find him shifting on the cot, his cheeks flushed, his hair damp with sweat. His eyes judder beneath the lids. The doctor takes his temperature: 39 degrees, not dangerous yet, but quite high enough to worry.

Yinsen swears softly and lifts the dressings on Stark’s incisions. No sign of infection. Instead, it’s the stethoscope that reveals the problem: there’s fluid in the lungs, fine sharp crackles on each breath. Pneumonia.

“You can’t do anything the easy way, can you?” he murmurs without heat. It’s no fault of the patient’s, he knows, but joking will help keep him sane.

There’s little enough he can do. He puts Stark on an antiviral and an even higher dose of antibiotics, makes sure he’s getting enough fluids, and settles in to manage the fever. At least the cold cave air is finally good for something.

Stark worsens all day. By evening he’s over 39.5, twitching restlessly on the cot. His lips and throat work around the ventilator, and Yinsen wonders who he’s seeing—what he’s trying to say. Yinsen doesn’t remember: does the man have a family, someone to visit him in fever dreams? Or perhaps the hallucinations are less pleasant; the doctor can only hope he isn’t reliving what the Ten Rings did to him. Better that he be off in some nonsensical Wonderland, building a solid gold aircraft carrier or whatever filthy-rich American engineers do when they dream.

It’s a good thing Stark isn’t strong enough yet to thrash much. Yinsen doesn’t think he would deal well with being held down.

Morning is, as ever, difficult to track, but the cave lights are back on and the air is slowly warming when the fever breaks. Yinsen’s been bathing his patient’s face and neck with cool water for the last hour, keeping up a gentle patter of inconsequential talk, so he’s bending close enough that his hands notice first: the furnace heat of Stark’s skin has diminished a little. The thermometer confirms it. 39.2.

“I’m not sure whether you are lucky, tough, or both,” he tells the inert body, “but whatever it is, I’m grateful.”

\---  
\------  
\---

[TBC]


	7. Interference

**Summary for the Chapter:**

> _“No. No, hand it over. I can do this.”_
> 
> _“No you can’t, Stark. You’re not moving your arms for another week.”_
> 
> _“Well, I’m sure as hell not gonna sit here like a little kid while you spoon-feed me. Give it.” Stark flicks his fingers, an unmistakably imperious gesture. The effect is somewhat ruined by the shallow, careful breaths that break up the demand, and by the fact that he can’t lift his arm to do it._

**Notes for the Chapter:**

> (run interference: to protect someone from unwanted attention by diverting it elsewhere)
> 
> I'm back! I'm so sorry for the long wait. The holidays were crazy, and then things only got _busier._ What is my life?
> 
> As ever, this chapter was betaed by [fledisthatmusic](http://archiveofourown.org/users/fledisthatmusic/pseuds/fledisthatmusic) and [MountainRose](http://archiveofourown.org/users/MountainRose/pseuds/MountainRose), both of whom are _amazing_ and indispensable.

When Tony blinks his eyes open, he’s as surprised as anyone.

He’s been drifting for... he doesn’t know how long. The drugs limit his awareness to a tiny circle of clarity hemmed in by heavy fog. Without sense data to measure it by, time pools and stretches like warm taffy. Here and there, diffuse sensations float through the haze -- light against his eyelids, muted pain, faint wavering words -- but he can’t estimate the stretches between them.

Then he opens his eyes. Blurry gray above him. It’s cold. Air forced in and out of him, but the pain on each breath is kind of muffled. Familiar sensation of choking. Time permits his fumbling grasp without slithering away. There’s something round and pale... He blinks several times (slowly, through his leaden eyelids) and it resolves into a face. Bald head. Glasses. Beard. Yinsen.

...He’s getting tired of not recognizing things.

“Awake yet, Stark?” the doctor asks.

Tony makes the mistake of trying to answer, and oh, _there’s_ the pain. He freezes, holding himself rigid while he fights back a spasm of choking that would’ve torn him in half, and then concentrates for a while on riding out the one that only cracked open his chest. Gradually, the drugs’ gentle buffer wraps him back up, and he lets his eyes float back open.

“Easy,” Yinsen soothes, as Tony’s hearing fades back in. “Sorry, Stark. Don't try to talk yet.”

 _Yeah, I could've figured that one out myself, thanks._ He tries to glare, but everything’s blurry and he’s not sure that he’s aiming it at Yinsen’s actual face. He’s too tired to put any real force behind it anyway.

When he rolls his eyes downwards to glare, though, something intrudes on his peripheral vision. He strains to look farther down without moving his head, and more details come into focus. Something slender, black, curving away from his chest...

Why the _fuck_ is he still hooked up to the car battery?!

Adrenaline clears his vision _right_ the hell up, and this time he knows he’s glaring straight at Yinsen. If the force of that glower comes at least as much from fear as anger, he sure isn’t going to admit it. He needs that anger, damn it, because the adrenaline’s also making his heart pound, and he can feel it hitting the housing’s baseplate -- God, it’s like a jackhammer, chiseling right into his heart -- but he is _not_ going to let that distract him from finding out _why he is still running on batteries._

Either Yinsen isn’t parsing the glare, though, or he’s deliberately deflecting Tony, because he doesn’t answer the question. Instead he wraps his hand around Tony’s. “You must be awake if you can look at me like that. Can you tap out the first five prime numbers for me?”

Yinsen goes through the same series of did-I-break-his-brain tests as before, Tony glowering at him the whole time.When they’ve finished, the doctor’s free hand starts fussing with something away over Tony’s shoulder. “You’re doing very well, considering. How’s the pain?”

How does he _think_ it is? Tony closes his eyes and wishes he could snarl properly. Honestly, though, it’s not as bad as the last time. His heart isn’t hammering so hard against the back of the housing anymore, and whatever’s floating through his veins really is helping. He taps seven times.

Yinsen nods. “All right. Just a moment, Stark. I’ll get you something for it.” He’s gone for a moment; Tony closes his eyes and tries, unsuccessfully, to drift a little. Something shifts in his arm. The doc’s back, leaning over him: “How is it now?”

Tony considers, blinking sleepily. Tap-tap-tap-tap.

“Good.” Yinsen pats his hand. “Because I’m afraid you won’t like this next part at all.”

Well. _That’s_ not even a _little_ ominous, is it? Tony narrows his eyes at Yinsen and waits for the other shoe to drop.

\---

Stark talks quite a lot, for a man muted by a breathing tube. He puts whole sentences into the set of his eyebrows and the twitch of his hands. Yinsen doesn’t doubt that he’d manage paragraphs, given time and lighter sedation.

Yinsen wouldn’t consider leaving the tube in for that long, though, not with a conscious patient... and conscious Stark is, by now. That glare, flicked back and forth between the battery leads and the doctor’s face, spoke volumes. If Stark is coherent enough to ask _that_ question, and his pain is down to a four, then it’s time to talk about taking him off the ventilator.

“You’ve been asleep for almost four days, and you’ve had a mild bout of pneumonia,” he begins, wanting to orient Stark before asking him to make any decisions. “Your fever’s gone down, and the infection’s under control, but there’s still fluid in your lungs. It’s started to interfere with your breathing.”

Stark twists his eyebrows up, the expression lopsided and incredulous.

“Yes, I know, it isn’t the first.” Yinsen smiles without mirth. “It will get worse, though. We have to get the fluid out. I could suction the tube manually, but that’s an ugly business. Better to take you off the ventilator and have you cough it up.”

Somehow, the incredulity is only _more_ concentrated when Stark’s eyebrows pull back down. His fingers twitch against his sides.

“Of course it will hurt, but it’s that or drown.”

Stark’s pupils dilate visibly, his fingers clench, and his pulse jumps under Yinsen’s fingers. He draws his brows down even farther, though, fixing Yinsen in that same outraged glare.

The doctor’s smile is anything but apologetic. “Ready to try breathing again?”

...Tap.

“Good.” With his free hand, Yinsen reaches up to the ventilator to start dialing it down. “A quick test, first. I’m going to turn off the positive pressure here, so you’ll be on your own. Breathe from your abdomen. Three, two, one...”

He switches over to unpressurized oxygen, and Stark’s chest falls still. The patient clamps his eyes shut, fingers tightening on Yinsen’s hand. For a moment, Yinsen’s afraid the man won’t be able to do it, muscles still too raw to drag in air on their own; but then he sucks in one shallow, hitching breath, another, and another. Slowly, they ease into a pained but steady rhythm. Stark’s oxygen sats dip, stagger, and stabilize.

Yinsen’s jaw tightens. In an actual hospital, it would be a borderline case; he doesn’t like taking Stark off the ventilator yet, not until breathing hurts him a lot less. In an actual hospital, though, he’d have other ways to deal with the pneumonia...

He puffs out a silent breath, unnoticed by his patient, and checks the man’s vitals one more time. “That’s good, Stark. All right?” He gets one tap in reply. “Then over you go.”

\---

The moment Tony taps out, Yinsen’s moving again. He frees both hands and slides them under Tony’s shoulders; pain flares white through Tony’s chest as he’s turned onto his left side. He barely has time to recover from that before another rush of cold spreads out from his arm and suddenly he’s shivering, muscles waking up and scrambling against the cave’s chill. He doesn’t care about that at _all,_ though, because the muscles of his throat are waking up too, he hadn’t realized they were asleep but something must have been holding them down because now his gag reflex is alive and shrieking, thrashing against the breathing tube in a violent retch, and he barely feels the clicks of tubing because the thing is sliding up his throat --

It comes free, and the coughing rips him in half. Every spasm claws at the sliced-up muscles of his chest and belly and grinds his ribs against the steel between them. Stars flare behind his eyelids as he curls involuntarily around the hurt, the helpless reflex only making it worse when it tears open what little healing had begun while he slept.

A million years later, the coughs begin to subside. When he finally manages to stop, he just lies there _very very still_ and concentrates on breathing.

Something touches his face. He flinches back, but it’s barely a twitch, and the cool touch follows as he gasps again. “Breathe,” admonishes a gentle voice above him. “Easy. Easy.”

Tony blinks his eyes back open to see Yinsen holding something transparent against his face. The air’s cold and dry underneath, but it makes breathing easier: he finds he can take shallower breaths, go easy on his ribs. In, out. The rhythm’s strange; it doesn’t really come naturally, like it should. He stares at Yinsen and works at it.

 _Where’s the arc?_ he tries to ask, when he thinks he’s done hacking for a good while. _Tries,_ because what comes out when he opens his mouth is just a thin croak; his throat’s sore like he’s been yelling for hours, and dusty-dry to boot. It sets him coughing again, and _ow,_ didn’t he already do this part?

“Easy,” Yinsen soothes, as Tony’s hearing fades back in. “Don’t try to talk.”

Tony clenches his fists and tries again, with no better results.

“For God’s sake, Stark,” the doctor mutters, turning away. When he comes back, he lifts the oxygen mask and presses the rim of a tin cup to Tony’s lips, free hand lifting his head to let him drink. “It’s water. Just a little.”

It’s cool, a little brackish, and absolute heaven on his abused throat. He offers a sickly half-smile in thanks, then tries again: “Whr’s th’arc?”

Yinsen must be fluent in mumble, because this time he doesn’t try to pretend incomprehension. “It’s safe.”

 _Not what I meant._ “N’why’m’ still’n th’batt’ry?”

“Don’t worry. It will last a few more days.”

Tony glares at him. _“No,_ why isn’ th’arc n’ th’hous’ng?”

“Wiring trouble. It’s fine, just rest.” Yinsen shushes him absently, looking over his shoulder at some piece of machinery or other.

Wiring trouble? What’s that supposed to mean? Did Yinsen find some last-second compatibility issue? Is the arc not going to _fit_ or something? Jesus, did he just go through all this for _nothing?_ And now the man won’t even _look at him--!_

Tony tries to lever himself up on his elbows, which _shit fuck bad idea OW._ He’d thought coughing hurt, the way it ground his ribs against the steel -- this is _worse,_ that same awful grind on top of pulling at the incisions, and the muscles he’s trying to move _do not want to go._ Shit, shit, shit, he’d forgotten this part -- _you won’t be able to move your arms,_ Yinsen had said, the muscle connections cut away with his sternum, and they’ll have to heal into the titanium before he can do stupid shit like try to sit up --

Searing agony detonates in his chest, burning outwards from the reactor housing, and his vision whites out completely.

_Balls._

The uneasy, foreign rhythm of his breath is the first thing to come back, oxygen deprivation urging him out of the haze and forcing him to think about breathing again. _In, out, in, out,_ and while he works on that, the rest of the world settles into place around him. Yinsen’s looking him in the eye now at least, but he could do without the -- is that actually _fear?_ \-- in the doctor’s face, or the slow embers buried in the middle of his own chest.

“--ark. Stark!”

He blinks, squinty-eyed, in the doctor’s direction. “Littl’ h’lp h’r?”

The tension drops out of Yinsen’s shoulders like water out of a suddenly-bottomless bowl. “Don’t do that again,” he breathes.

“G’nna haf’t’ sit up s’mtime.”

“But _not_ now. You’re not ready, Stark.” Warm, steady hands move to check the bandages on Tony’s chest. He lets his head fall back, lets it happen. “We had this discussion, remember? Six weeks to heal, _minimum,_ and you do not start trying to exercise until I tell you to.”

...At least he isn’t saying “I told you so.”

\---

“No. No, hand it over. I can do this.”

“No you can’t, Stark. You’re not moving your arms for another week.”

“Well, I’m sure as hell not gonna sit here like a little kid while you spoon-feed me. Give it.” Stark flicks his fingers, an unmistakably imperious gesture. The effect is somewhat ruined by the shallow, careful breaths that break up the demand, and by the fact that he can’t lift his arm to do it.

Yinsen sighs and sets down the spoon. Stark’s been fully awake for several days now, and every meal since he woke has been the same. The man’s still bedridden, shivering and sick from the blood-loss, unable to sit up or even move his shoulders, but he _insists_ that he can feed himself. Each time, it takes longer for Yinsen to wear him down and make him accept help; each time, he takes the meal in sullen silence.

Stark taps fingers and thumb together. “Well?”

Yinsen is sorely tempted to give in and let him try.

Instead, he shakes his head for the thousandth time and refills the spoon. “You’d tear the wound open again. Open up.” Stark opens his mouth -- not for food, but to retaliate, and Yinsen contemplates stuffing the spoon in anyway --

Whatever he’d have said is drowned out in a metallic clatter. Someone shouts through the door.

Yinsen drops the spoon and jumps to his feet, whirling to face the door as it opens and Raza’s thugs pour through. He throws both hands on his head and does not move, not even when blankets rustle behind him and a bitten-off groan tells him that Stark tried to rise, too.

 _Stay_ down, _you fool!_

Behind his thugs, Abu Bakaar lumbers in, glowering at his prisoners. He looks Yinsen over only cursorily before turning a stormy frown on Stark and barking at Yinsen in Dari. “Why isn’t he up? Dusek, Zadran, get him up.”

Two of the men move on Stark, reaching for his shoulders, and Yinsen steps in front of them. “No! No, please don’t.” He forces a smile, though his legs are shaking. “He can’t. Not yet.”

Bakaar snorts at him. “Get out of the way.”

“He _can’t,”_ Yinsen repeats. “Eight weeks, I told you--”

An irritable hand-wave cuts him off. “And I said _get out of the way.”_

All at once, something like anger or irritation or strength flows through Yinsen, and somehow he finds it in himself to glare _back._ “No, _look.”_ He turns to bend over Stark, moving slowly enough to avoid getting shot, and reaches for the bandages. Stark’s due for a dressing change anyway. As he lifts the gauze away, gingerly easing it off the wounds and making sure to draw out what he’d packed into the open socket, Stark bites back another soft cry; Yinsen apologizes, but only silently. “Look,” he says again, waving a hand at the raw, stitched-up mess. “We need more time to heal. He _can’t get up yet.”_

Bakaar, unfortunately, is not so easily swayed. “It’s time to get him back to work. You’ve had two weeks now.” Another gesture sends the guards forward again. “Get him up, or I will.”

With another silent apology, Yinsen sticks two fingers into the empty reactor casing and wiggles them, letting the movement highlight the chasm in Stark’s chest. They don’t so much as touch the sides. “Do you not see this _hole?”_ he demands, trying to put all his indignant incredulity onto his face. “He can’t lift his arms. He can hardly breathe. What makes you think he can _work?_ I told you eight weeks from the start, and eight weeks it must be!”

Dusek and Zadran back off. Is it just Yinsen’s imagination, or do they look a little pale?

Yinsen pulls his hand back and folds his arms, staring Bakaar down. The big man’s glare is a little cooler -- certainly more calculating -- as he looks the doctor up and down. The tension stretches out, and the tremors start up again somewhere around Yinsen’s knees; he locks them. Looking weak right now would be suicidal.

“You said eight weeks to recover fully,” Bakaar rumbles at last. “You didn’t say he’d be _useless_ for eight weeks.”

Cold sweat breaks out on the back of Yinsen’s neck. Useless prisoners don’t last long down here. “He’s healing. It takes time. When it’s over, he’ll build the mi--”

Bakaar snorts.

 _Think fast. Think faster._ Yinsen clamps his hands together behind his back. “...We could start on the plans? I’ll draw for him. The surgery hasn’t affected his brain...”

A long, dark stare makes his hands shake and sweat roll down his brow. Finally, though, Bakaar cracks a slow smile. “All right, Doctor. Eight weeks. Get to work on those plans.”

The man turns to go, and Yinsen drops, boneless, onto the other cot. He looks back up, though, when Bakaar snaps off a command in quick Czech and Dusek breaks off from the guards, heading for the medical supplies in the corner. When Yinsen can’t restrain a small, protesting noise, Bakaar chuckles: “I think you’ll both work faster if he doesn’t sleep so much. No more sedatives til you’ve built my missile.” The doctor opens his mouth to protest -- “You’re lucky I don’t take the painkillers,” Bakaar snaps.

Yinsen can only watch, helpless, until they’ve all left.

\---

The door bangs shut behind the last of Beardy’s gang, and oh right, _breathing,_ kind of need to do that. Tony gasps in as deep a breath as he can manage, his mind racing. There are a hundred things he wants to say right now: most of them basically boil down to _what the fuck was that?!_

He thinks he can be forgiven for not opening his mouth immediately, though. Instead he clutches the edges of the cot and concentrates on breathing past the fear, the confusion, and the fierce stabbing where his heart’s slamming itself against the reactor casing. _In, out. Shallow and steady, come on, I’ve been working on this._

When he can see straight again, he lets his hands unclench. “What the fuck was that?” he demands, and then can’t hold back a breathless groan.

“He wanted to get you up.” Yinsen’s back on the stool by the cot, cradling Tony’s forgotten dinner between his palms and staring into it with a glaze that speaks of adrenaline crash. The bowl quivers gently in his hands.

A high-pitched, helpless bark of laughter escapes Tony; he regrets it instantly. “Yeah, I got that much. What’d you _say_ to him?”

Yinsen puts the bowl down and reaches for Tony’s wrist. “That we would start work on the drawings immediately.”

“What? No. I’m not--”

“I know.” The doctor shakes his head, letting go to stand up and head across the room. “We have to give them something. Start with the obvious. Start with the overview. We just have to stay productive. He agreed to the full eight weeks’ recovery, but--”

“Whoa, _stop the presses.”_ Tony twists his head to stare, hands clenching at his sides. He wasn’t exactly banking on being useless for that long. “What do you mean, eight weeks?!”

Doc glances back over his shoulder. “Do you want the extra time or not?”

...Oh. Tony blinks. “Right. Uh, thanks.”

Yinsen quirks a wry smile, turning back to the cot. As he lays out the fresh bandages and gauze, he tosses back: “What, you think that was the first time? You didn’t exactly jump right up after the first surgery, you know. I’ve been running interference for you for weeks now, Stark.”

Tony’s breath hitches. “Guess I owe you one.”

“I’ll hold you to it.”

\---  
\------  
\---  


[TBC]


	8. Cure Monitoring

**Summary for the Chapter:**

> _He lifts a hand, carefully moving it to the center of his chest. The glow makes his fingers ghostly as they lower, trembling, to tap gingerly on the face of the arc. Not a good idea, maybe -- the touch echoes down through his chest and shoulders and spine -- but he had to know. It’s real. It’s there. It’s... part of him._

**Notes for the Chapter:**

> (cure monitoring: the observation and management of the process by which resin or concrete achieves a more stable form)
> 
> Well. Um.
> 
> I am _so sorry._ I don't really have much of an excuse. A nasty combination of RL delays and sheer writer's block, that's all... but it was plenty to delay this chapter with. Sweet spangly Joker on a rocket-powered pogo stick, this chapter was difficult. O_o The next one... shouldn't take nearly so long.
> 
> Don't worry, though. Regardless of delays, and come hell or high water, I will not abandon Revision. So help me, this fic _will be finished._
> 
> On a lighter note, holy shit, guys -- [szzt](http://archiveofourown.org/users/szzzt/pseuds/szzzt) made me [FANART!](http://szzzt.deviantart.com/art/Stark-353461530?q=gallery%3Aszzzt&qo=0) It is gorgeous and evocative and I kind of want to cuddle it. :D The scene depicted is coming up, either in the next chapter or the one after. You should all see this art, and deliver appropriate kudos to the artist.
> 
> As always, this chapter was betaed by both the flawless [fledisthatmusic](http://archiveofourown.org/users/fledisthatmusic/pseuds/fledisthatmusic) (formerly 2twistedforcolortv -- she's on AO3 now, go see!) and the expert [MountainRose](http://archiveofourown.org/users/MountainRose/pseuds/MountainRose), without whom I probably would have given up ages ago. You are both truly amazing.

“Time to get up, Stark. Rise and shine!”

Tony squeezes his eyes shut and holds back a groan. Maybe if he lies really still, he can sleep a little longer. Try to sleep. Whatever. Even his uneasy dreams are better than lying here shivering, and the nightmares don’t usually last long. It’s worth it, is all he’s saying.

Fingers prod at his shoulder. “Breakfast is ready, and after that we’re starting your therapy.”

Okay, what? Tony drags his eyes open, blinks until Yinsen swims into focus. Squinting, he mumbles, “Did’n r’member therapy.”

“What, you thought I’d let you start lifting cruise missiles with no preparation? You’ve got six weeks of PT to come, Stark. Wake up.”

Screw that. Tony is not _up._ Up is not in his vocabulary right now. Yinsen can keep his _up_ and stick it where the sun doesn’t... where the fluorescents don’t shine. Tony grumbles something indistinct and shuts his eyes again.

“Stark?” At the lack of reply, Yinsen leans closer; Tony can feel his breath. “Do you want to be able to lift your arms in a month, or not?”

Now that’s just playing dirty. Tony allows himself one last long blink. “Okay, okay. ’M _up.”_

Yinsen favors him with a small smile and a faceful of spoon.

...This was not worth it. “What.”

“Breakfast?”

“Bein’ generous with th’def’nish’n there.” Tony eyes the silverware narrowly. Over-stewed bean slime is not his idea of breakfast. He can’t even tell if it counts against his dislike of solids in the morning.

The doctor just raises an eyebrow and waggles the spoon.

When they’ve finished the battle of wills that has so quickly become traditional at mealtimes, Yinsen sets the bowls aside and disappears behind Tony’s head. Small scrapes and clanks of equipment moving; then clothing rustles, and a warm presence settles behind him. He tips his chin back a little and gets a nice view right up Doc’s nose.

Yinsen looks down, mercifully obscuring Tony’s view of his nostrils. There are some things a guy doesn’t even need to know about his cellmate, much less his doctor. “All right, Stark. You should know first that we’re starting earlier than I’d like. You should have more time to heal before we do any of this. But we are where we are, and that just means that you _must_ tell me if you feel any sharp pain or grinding sensations. Understand?”

“Yeah, sure.”

Doc cocks an eyebrow. “Because if you don’t, you’re going to tear your stitches. Or worse, tear your pectoral muscles off the housing. Do I need to list the consequences for you?”

Nope, Tony’s brain is doing that part _just fine,_ thanks. He swallows hard. “...No, I got it.”

“Good.” A warm hand (seriously, was it this cold in here before?) closes around each of Tony’s forearms, just above the wrist. “We’ll start with elbow flexion. I want you to lift your hands up from your sides, leaving your elbows where they are. I’ll support you, like this.”

Simple enough, or it should be, but Tony’s whole upper body immediately starts protesting the movement. “Yeah. That’s kinda sore,” he says, trying for conversational, as his hands clear the four-inch mark.

“That’s normal. Let me know if it gets worse.”

The doc has him repeat that exercise a few times, then flex his wrists, which is pretty much painless; apparently the wrist bone isn’t connected to the chest bone, unlike everything else in his whole goddamn body. When they finish with that and move on to rotating his shoulders, though, he has to stop pretty much instantly. “Worse!” he grits out, his head jerking back involuntarily as fire blooms from the middle of his chest.

Yinsen immediately takes all the weight, gently lowering his shoulders back into place. “All right. We’ll leave the shoulders alone for now.”

Tony just lies there for a minute longer, until the burning fades enough to slip back under the morphine. When he lets his eyes open and his fists loosen, Yinsen’s leaning over to look down at him.

“Better, Stark?” At Tony’s nod, he shifts his grip back to Tony’s forearms. “Good. Let’s try the elbows again.”

Tony is definitely starting to understand why people hate their physical therapists.

\---

Tracing paper is not, in Yinsen’s experience, a particularly resilient material. He has worked with it on occasion, and each time he’s tried to be sure of his design before transferring it to the onionskin, fearing that too-vigorous erasure would tear the fragile pages. It’s a good thing, he reflects now, that the Ten Rings haven’t provided paper of any real quality. The waxy, crinkled sheets they deliver bear occasional stains (which have made him quite sure that he never wants to know what they were once folded around), but they’re sturdy... sturdy enough, perhaps, to stand up to Stark’s perfectionism.

“No, no, Jesus. It’s an arc. Arc of a circle. Radius four millimeters. Sixty degrees. No, left from the point of intersection. Your other left. _Other_ left.”

Yinsen levels his gaze at the opposite wall and reminds himself, for the third time since breakfast, that striking his patient is entirely unacceptable.

“Okay. Trying again. Start from the origin, bottom left of the page, right there. Origin for that curve will be at x one-fifty, y sixty-three. Scale bar’s over there. _There._ Seriously, it’s not that hard. Component 16 just needs to fit _inside_ component 12. Wh -- no, don’t put that pencil down. We’re not done here. Pick it up. Yinsen. C’mon.” Stark’s eyes flick up from the pencil, which now lies perfectly parallel to the table’s edge, to Yinsen’s face.

“This is not working, Stark.” Yinsen picks each word out precisely. Enunciation helps cool his annoyance.

“Yeah. Got that much.” Stark drums his fingers on the cot’s canvas. The narrow glare that he fixes on their makeshift drawing board (a piece of heavy cardboard, from the box of canned beans) could be either annoyance or calculation. “Bring that piece of crap over here.”

Yinsen raises an eyebrow. “You can’t be considering trying to draw it yourself.”

“Not all of it. Can’t move from the shoulder. Got that much this morning. But I also got that my wrists -- ” and he ticks the joint in question back and forth while he pauses for breath -- “are just fine. So bring that thing over. Prop it up like a nightstand, will you? I’ve got an idea.”

It is actually, Yinsen’s forced to admit as Stark lays it out, not a bad idea. They'll prop the drawing board almost vertically, beside the cot, and fold a pencil into Stark’s dominant hand. Since Stark can’t move his shoulder, Yinsen will do it for him -- grasp his arm and lift it out to the side, so that the engineer’s forearm and wrist rest on the page. From there, Stark will be able to draw using only the muscles of his wrist and fingers; when he needs larger movements, or two hands, he’ll ask for help. They’ll probably present a less than dignified image to the cameras, moving different joints of the same arm, but Yinsen can’t bring himself to care.

“You know, if we’re careful, this could even be therapeutically useful,” he muses as they finish propping the board in place. “It is not so different from the exercises I’d planned for tomorrow.”

“Huh.” Stark spares him a glance, eyebrow cocked. “Think it’ll make me hate my life any... any less than the ones this morning?”

Yinsen gives him a sliver of a smile before gently lifting his arm, moving it into place against the page. The movement isn’t painless: Stark pales at the pull, however indirect, on his chest muscles, and his breathing hitches. Out of respect, Yinsen sits quietly to let him recover.

“Guess not,” Stark gasps finally.

“You will be able to distract yourself, at least,” Yinsen points out.

“There’s that.” The wrist flexes experimentally, and Stark begins scratching at the page. Yinsen’s impressed -- even through the pain and the morphine, his hand is almost steady.

They don’t speak again for a long few minutes, save Stark’s occasional murmur calling for a ruler or protractor. The pencil skitters over the page, sketching out a few square inches of... something. Yinsen will not pretend to know what it is, especially not from the fragmentary diagram. The engineer’s brows draw downwards as he works; he glares at the paper with progressively greater frustration, his movements growing more deliberate and forceful even as his fingers begin to shake.

After the fifth time going over a particularly complex curve, trying unsuccessfully to smooth it out against the jags put in by his tremors, Stark flattens his hand against the page and squeezes his eyes shut. “Goddammit,” he hisses.

Yinsen reaches for the pulse in his other wrist. Rather higher than it has been, but strong. “You’re doing well, actually.”

Stark huffs out what would be a snort if he had the breath for it, turning his glare on the ceiling. He taps the pencil’s butt end against the paper, curiously well in time with his heartbeat. “What draft are -- are _you_ looking at? These lines’d shame -- an art student -- with Parkinson’s.”

“It isn’t as though this drawing needs to work.” When that doesn’t get a response, Yinsen lets the wrist go and looks his patient over. Stark is breathing even more shallowly than usual, and the stare fixed on the ceiling lacks the laser-sharp indignation of the ones Yinsen earned over breakfast. “Stark?”

“I _know._ Dummy missiles.” His free hand flicks dismissively. “Still. A guy’s got -- got his pride. B’sides, f’I can’t do this -- I can’t draw what _does_ \-- need to work.”

The breathlessness is definitely getting worse. Yinsen twists to pull his stethoscope from the kit. “You’ll only improve as you heal.”

That pained huff would have been a laugh, probably. Stark presses his cheek to the canvas.

Auscultating Stark’s chest is tricky at the moment, between the tender swollen skin and the crackle of the fluid remaining in the lungs. Still, even once he finds a spot where he can hear, Yinsen doesn’t think anything sounds abnor... well, more abnormal than expected. Perhaps a faint metallic echo, but that’s probably the tapping pencil. The pneumonia’s still resolving well, and that level of exertion shouldn’t have exacerbated it this badly.

“Talk to me, Stark.” Yinsen leans close. “You’re having trouble breathing.”

Stark cracks an eye open. “Yeah.”

“What hurts?”

He turns his head away. “What d’y’think?”

“Stark...”

“Chest. Ribs. Heart.”

Alarm jolts through the doctor. “Your _heart?”_

“C’n feel it beating. Hits th’housing when s’racing.” He drums two fingers on the cot, taut canvas thumping in time to his pulse.

God forgive them. Stark can _feel_ that? Yinsen grabs his entire kit this time, drawing out another dose of morphine; Stark’s nearly due for his next, and it will help lower his heart rate as well. “Give me a number.”

“Oh, fuck you.”

_“Stark.”_

“...Sev’n.”

Yinsen doesn’t hesitate to dose him. The drug takes a long minute to take effect, but once the tension starts to bleed out of Stark’s muscles, the doctor risks moving his drawing hand back to the cot. Gently, he tugs the pencil away from the unresisting fingers. “I think that’s enough for today.”

“W’just _started.”_ Stark frowns.

“Yes, we did. And now, we are finished. Hm?” The drawing board is set aside on the far workbench. Best to send a message here. “We’ll try again tomorrow.”

“We’ve gotta work,” the man insists.

“You have to _rest.”_

“Yinsen...” He shifts, as agitated as he can manage to be with a fresh dose in his veins.

“Stark.”

“...Jesus.” Stark shuts his eyes again, this time less in annoyance than exhaustion. Good. “Anyone ever... tell you you’d... make a great mom?”

That hits much closer to home than Yinsen is willing to admit. He forces a smile and settles back down beside the bed. “A few times. I usually have nurses to handle this part.”

That gets him a quirk of a half-smile, and a mutter that might have been “prettier than _you,”_ before his patient drops back off to sleep.

Over the next few days, they fall into something like a routine. Wake with the cave lights. Eat. Wash. Physical therapy. Rest. Eat. Draft. Rest. Eat. Sleep. Yinsen isn’t about to tell Stark, but he’s impressed by the speed of the man’s progress. Whether in drafting despite his barely-mobile arms or in recovering on short rations, cold air, and too much stress, Stark moves far faster than he has any business moving.

By the end of the second day, they’ve completed something that resembles a set of construction drawings, and Stark’s restlessness is approaching truly dangerous levels. Yinsen will admit that he isn’t sure where the danger originates: it’s probably just from the risk of overenthusiastic movement straining Stark’s injuries, but it might also be from the risk of driving his doctor to violence. The man is lucky to be sleeping eighteen hours of the day still; while he’s asleep, Yinsen can gather his patience and tamp it firmly back into place for the next round. Tea and simple tidying tasks help. Fear does not.

Late on the third day, he’s sipping from his battered mug and trying to make sense of Stark’s drawings when the man himself awakes. It’s with a groan, as usual. “Didja get the license number?”

Yinsen peers at him over the drawings, lifting an inquisitive eyebrow.

“Of th’truck that hit me.” Gingerly, Stark flexes his wrists and elbows, then twitches his shoulders. “Hell of a therapy session, Doc.”

“I thought you were glad of it.” Yinsen smirks, putting the drawings down. “You lifted your screwdrivers unassisted, if you remember.”

“And range of motion’s improving. Blah blah.” Stark rolls his eyes. “S’not exactly an Olympic gold.”

“It’s a significant improvement.”

Stark grunts. “Not enough of one. We’re running out of time.” He casts a significant look over at the battery.

There’s a day or more left yet, Yinsen could argue. The trouble is, Stark’s right. Twenty-four hours is a dangerously thin margin of error, should something be truly _wrong_ with the reactor or housing. This morning’s PT proved that the man can handle the necessary tools... He reaches for Stark’s pulse. “I know. Give me a number.”

Stark submits to the usual check-up with less grace than normal, fidgeting constantly, but Yinsen can hardly blame him for his anxiety. When the doctor is satisfied that Stark’s no sorer than he should be, he picks up a small cardboard box from the nearer workbench. Faint blue light spills from its top.

“Wiring trouble, you said.” Stark squints at the box.

“What?”

“Why you didn’t hook it up the first time. The arc. Wiring trouble.”

“Ah. Yes.” Yinsen opens the box. Arc-glow lights his face from below. “I believe something is wrong with the reactor’s connector. It doesn’t quite fit the port in the housing.”

Stark’s eyes snap immediately to the dangling plug, and Yinsen can _watch_ as he pulls engineer-focus over himself like a cloak. “Show me.”

It takes some maneuvering with a couple of pillows and Yinsen's little shaving mirror, but the doctor manages to show Stark the problem. The three metal pins that actually make the connection are subtly out of place; when Yinsen tried to plug the arc reactor in the first time, they'd missed their sockets. “I couldn't have fitted the reactor without stripping off the plug's plastic cover,” he explains.

“Yeah, bare wires’n th’chest, sounds like fun." Stark peers into the mirror, huffing a disgusted sigh through his nose. “How the hell’d we miss this? Is that one _bent?”_ When Yinsen can only shrug, Stark sighs again. His fingers twitch. “S’an easy fix at least. Get me the precision screwdrivers -- pair of wire cutters -- th’smallest needle-nose pliers -- soldering iron -- coil o’solder -- n’two pairs of tweezers.”

Yinsen fetches as ordered, laying out the tools on a stool within easy reach. He’s reminded, perhaps more disconcertingly because the comparison is so appropriate, of preparing surgical instruments. “Can you change the connector to fit the socket, or will you need me to modify the housing?”

“We’re in luck, Doc. Just th’plug. Hol’this f’r me, wouldja?”

Thank heaven for small favors. Yinsen settles in beside the cot, resigned to playing work-stand for a while. Stark’s work doesn’t seem to need any movement above the elbows; he just snaps off part of the connector’s plastic cover and sets it aside, giving him free access to the misplaced pins. He sets about snipping wires, tugging at tiny parts, soldering new connections back into place, and Yinsen realizes with a small shock that he looks _animated._

For all that he kept every ounce of his sarcasm and impatience, Stark has been subdued since the second operation. Of course he has -- it was major surgery -- but looking at him now, seeing that fierce and driven grace flow so quickly back into his movements, Yinsen realizes that his listlessness was not entirely from the trauma and recovery. He’s alive now, for the first time since Yinsen put him under: picking up the tools was like picking up a missing piece of himself.

Oblivious to the introspection hanging over him, Stark puts aside the soldering iron and grabs the discarded piece of plastic cover. “Snap this back on, and it’s done.”

The plastic slots into place with a satisfying _click._ Yinsen turns the repaired connector over in his hands. It does look like a better match for the baseplate now, but there’s really only one way to find out for sure.

\---

Tony is holding his breath. It isn’t easy. Not that that matters very much, because fingers. Hands. _In his chest._ And yes, they’re Yinsen’s, Doc won’t hurt him this time, but he can still feel deep soreness and pressure as they pinch the little alligator clips and unplug his battery -- _unplugging him_ \-- and Christ, it can’t be real, it’s in his head, but tiny slivers of pain are already ghosting around near his heart... Moving would be a very bad idea right now, he has to remember that, has to remember that this is temporary and Doc is about to hook him up to something a lot better (pale blue glow in the corner of his eye), because otherwise he’s going to panic and try grabbing those hands himself and that just wouldn’t end well for _anyone._

Soft tap as the leads are tossed aside. The blue glow brightens, and yeah, there’s the arc. Circle of light, blunt plug, agile surgeon’s fingers unerringly finding the socket...

_k-CLICK._

Power surges through the pacemaker and Tony’s heart clenches, knocking the breath right out of his lungs. Fuck. _Fuck._ His vision hazes out and for a moment he can feel the fingers in his chest again, feel the pinch of the retractors, bare bulbs’ harsh light and rough hands pinning his shoulders --

“Stark?”

He blinks, gulping a deeper breath: ow, but worth it. His pulse is settling already. Okay. He’s okay. He manages to give Yinsen a nod.

Doc nods back. “Hold your breath again. I’m fitting the reactor.”

Tony obediently draws another shaky gulp and holds it while the doctor’s hands descend again. There’s a moment of achy pressure as Doc sets the reactor in its threads; then he twists it into place and the connectors lock with a solid _snick._ Tony’s much too preoccupied to notice, what with the movement tugging at the whole mess of knitting bone and tendons around the housing. _Shit._ Why the hell did he ever think this was a good idea?

When the burning starts to fade and he can see again, though, the first thing he notices is ice-blue light and a warm, thrumming weight seated deep in his core. It's weirdly heavy, but the buzzing is faint, barely even sore through his much-abused bones, and the thing is radiating _heat…_ It’s almost nice, after being so cold for so long. The warmth is loosening knots that he hadn’t even known were there. Not being cored like an apple is good, too: for all that the socket was supposed to support his ribs on its own, that gaping hole had felt so wrong.

Even better, though: no wires. He’s free of the battery. As he realizes that, a phantom ache runs up his right arm -- he hasn’t carried the thing in a week, but his muscles are remembering its weight. Oh, that’s _weird._ It’ll probably be even weirder once he can actually get up and walk.

He lifts a hand, carefully moving it to the center of his chest. The glow makes his fingers ghostly as they lower, trembling, to tap gingerly on the face of the arc. Not a good idea, maybe -- the touch echoes down through his chest and shoulders and spine -- but he had to know. It’s real. It’s there. It’s... part of him.

Finally, he looks up to meet Yinsen’s eye. The doctor is watching him, arms folded and face unreadable.

“S’good, Doc.”

Yinsen says nothing, but his shoulders relax. A faint, quiet smile quirks his lips.

Tony finds himself answering it with a broader grin. “Did it.”

“Yes, Stark. Yes, we did.”

\---  
\------  
\---

**Notes for the Chapter:**

> I love you guys. All of you. Everyone who reads this, I love you, and your reviews are like crack. (No, really, the neurophysiology is astonishingly similar. Rosie has taught me some surprising things.) Give an addict her fix? ;)


	9. Double-Blind

**Summary for the Chapter:**

> _When he looks back up, there’s an antipersonnel mine in her slender hands._

**Notes for the Chapter:**

> (double-blind: experimental design in which neither the researcher nor the subject knows the expected outcome)
> 
> I have no adequate explanation for how quickly this chapter came out. Seriously, I'm as confused as you are. Sure not complaining, though!

"R'mind me 'gain... why I c'n do this... b't not s't'up."

"This will put less strain on your abdominal muscles." Doc tugs the piece of cast-off rope through the last of Tony's belt loops, twisting it into an expert square knot over his left hip. "And I've told you, you may sit up whenever you like, so long as you allow me to lift you."

Oh, like _that_ counts. "L'k I said... not 'lowed t'sit'up."

Tony can't see Yinsen's face, propped up as he is with his forehead on the doctor's shoulder, but he's pretty sure the guy just rolled his eyes. "For God's sake, Stark, save your breath. Ready to continue?"

Tony glares at him, narrow-eyed and saying nothing. Hopefully that'll cover for his staggered panting; being lifted to a sitting position was embarrassing enough, but the way it's left him gasping is definitely worse. When he's managed to calm his breathing a little, though, he nods. _Gotta do it sometime._ "Yeah. Wh'n y'are."

"Then up we go." Steady fingers flicker one last time over the strapping that's keeping the weight of Tony's arms off his chest; then Yinsen shifts himself to fit right behind Tony, wraps his arms around to grab the makeshift belt, and lifts them both slowly to their feet.

Huh. That wasn't so bad. Tony'd expected this to feel different somehow --

He hasn't quite completed the thought when the strength falls out of his body like water from an upended tumbler. His vision goes blotchy, distorted, and grays at the edges. The air whooshes out of his lungs. Something really weird shifts downwards in his belly. He hangs there, limp as a rag, barely aware of the doctor's strong arms still holding him up; Yinsen's voice brushes him from a mile away.

When he comes back to himself, a minute or an hour later, he's still dangling ignominiously from Yinsen's grip, and also just realizing that he could _really_ use some air. He drags in a shuddering breath, distantly surprised at how much easier it is when he's upright. The reactor and its housing still press downwards, an aching, thrumming pull on his much-abused bones, but they don't seem to weigh so heavily on his lungs now that "down" is towards his feet instead of his spine.

Lying on his back: not ideal. He'll have to remember that.

Also, _ow._ Now that he's aware again, he's unfortunately able to recognize the dull headache pulsing behind his temples. He's sore all over -- probably another side effect of the Headrush from Hell -- and his heart is slamming heavily against the back of the reactor. Dragging his feet up under him is an exercise in frustration; making them take a little of his weight is even worse. If Yinsen tries to make him walk right now, he may actually hit the guy.

"Back with me, Stark?"

"No," he mumbles.

The doctor snorts. "Take your time. When you do get back, though, let me know; I was planning on getting you drafting once you can see straight."

Tony tips his head back, resting shamelessly on Yinsen's shoulder. His legs feel a little steadier, but now his chest and belly are taking up the complaint. "S'wrong w'th now?"

"I'll take that question seriously when you can look me in the eye and ask it." Yinsen shifts their weight to the side a bit, freeing up one warm, steady hand to grip the pulse in Tony's wrist. "Mm, not bad."

They stand there for a few minutes, locked in that awkward back-to-front hug, until Tony's vision clears up and his legs start to shake. "We just g'na stand here... th'whole time?"

"Whenever you're ready," says Yinsen, mildly. "There's a chair at the workbench for you."

"Then l's'go 'lready."

Walking is... just about as difficult and humiliating as Tony had imagined. He shuffles like a decrepit old man, making the kind of speed usually reserved for glaciers and board meetings. When they finally settle him down in the chair, he's wheezing helplessly, barely able to breathe, and he slumps against the backrest with a groan of impotent frustration. He's got four more weeks of this to look forward to? How is he going to keep from killing something?

Well. Drafting might help. Yinsen's already laid out the paper, he notes, as his vision clears again. Pencils near his right hand, ruler, protractor, compass, eraser, pens... and where the hell did Yinsen find a French curve down here? He smirks. "Been busy, huh?"

Yinsen just smiles and reaches to move his elbow into place.

\---

Twenty minutes later, Stark finally caps his pen and sets it aside. "This one's done. S'next?"

"Next, we get you back to bed. You were only meant to spend ten minutes upright the first time, you know."

"C'n at least lemme catch m'breath."

"Two more minutes." Stark nods once, letting himself slump over the workbench, free hand tapping a steady idle rhythm. Yinsen tugs the drawings and drafting tools out of his way. As he goes to put the paper aside with the other sheets Stark's finished, though, something familiar catches his eye. Frowning, he examines it closer. It can't be...

"Stark, is this an _IV pump?"_

The man coughs out a startled little laugh. "Yeah. G'd catch."

Yinsen stares at him. "Why..."

"Th'Rings won't know th'dif'rence... will'ey?" He twitches a finger towards the other drawings. "Top one's a Ferrari car'b'retor. AI rot'ry window-clean'r... un'er that."

Yinsen picks up the entire stack and leafs through it. Yes, now that he knows what to look for, the top two drawings are very, very far from missile-like. "Then why did you insist on such precision? You won't be building these, I hope."

"N't as such. See h'w only... part'f each one's inked?"

Yinsen had been wondering, actually. Each drawing is done mostly in pale, smudgy pencil, but here and there, a component or two or a scattering of lines is meticulously inked. He'd guessed that these were the result of Stark's frustration with hands still unsteady from pain or morphine - that the engineer planned to revisit the drawings when he could more reliably draw a perfect line. The distinctly satisfied, mischievous grin on Stark's face is making him reconsider that assumption quite thoroughly. "Yes..."

No further explanation is forthcoming, though. "Two min'ut's up. Back t'bed, yeah?"

How cryptic. Yinsen flicks one narrow-eyed glance Stark's way. He'll find out soon enough, he's sure. "You're ready?" He grips the rope belt again, feeling Stark lean back against him. "Up we go."

\---

Getting back to bed is _exhausting_. By the time Yinsen helps Tony lower himself onto the edge of the cot, Tony's wheezing horribly again, thin pants that do nothing to sate his hunger for air. He crumples down onto the canvas, Yinsen's arm under his shoulders the only thing controlling the fall... and somehow, the breathlessness only gets worse. His vision starts to gray out around the edges again. The nasty rattle of his breathing fills his ears, and he's afraid for a moment that he'll drown -- God, no, no, he said yes, why are they doing this again, _he already broke_ \--

\-- but then that strong slender arm hefts him back up, props him against a warm body. Breathing is instantly easier. A wracking cough still tries to split his chest open, and he still can't get _enough_ air, but at least there's oxygen in his bloodstream and he isn't hallucinating That Barrel. He leans there for a few minutes, utterly limp, and just forces himself to breathe.

It takes an embarrassingly long time to calm himself, to rein his desperate gasps in to mere panting, and to get his vision clear again. When he finally manages it, he realizes there's warmth on his back: Yinsen's hand is running gently up and down his spine.

"Backr'bs, Doc?" he wheezes finally.

Yinsen ignores the jibe, except as a sign that Tony's got his brain back and can talk again. "Your breathing isn't getting any better, Stark."

"No shit."

"I'm not surprised." He hasn't stopped rubbing. Tony refuses to think too much about how very soothing the touch is. "I had to remove parts of your lungs, you remember, and the housing still does restrict your chest's expansion somewhat. You've lost at least fifteen percent of your lung capacity... You need to re-learn how to breathe."

Tony would say something appropriately sardonic, but another cough rattles through him instead.

The doctor waits until it subsides before continuing. "There are techniques I can teach you, to aid your breathing. You won't be able to use all of them until you've healed more completely..."

"Better'n nothing," Tony grates.

"Yes, it is." Yinsen's hands shift, one on his shoulders and one in the middle of his back. "Rest your head on my shoulder. Now, if you pull your shoulders back and arch your back a little, like this..." The hand on his spine presses gently forward. Astonishingly, the movement doesn't hurt; rather, the arch of Tony's back seems to open his airways all by itself. "Like that. The movement expands your chest, gives you more room to breathe. Better?"

It _is_. He still can't take a really deep breath, but that little shift in posture is just about miraculous. He nods a little, then gets back to the business of gulping air like a landed fish.

"We'll work on it more as we go along," Doc says, after a while. "Do you think you can lie down again now?"

"...Prob'ly."

It goes better than he expected; Yinsen slips a lump of something soft -- folded-up jacket, if he had to guess -- under his back as they ease him down, so that even lying flat he can keep his back arched. It really does help, and even though the movement's still aggravated all the burning aches that spider through his ribs, he manages to relax into the cot with something like a sigh. Yinsen rustles around above him, and there's a sharp pinch in his arm; slowly, even the pain starts flowing away.

Sleep isn't too long coming, after that.

\---

Yinsen sits back from the workbench with a shallow sigh, rubbing one hand over his forehead. After seeing Stark dosed and down to sleep, he'd decided to inventory his supplies; quick though the man's recovery has been so far, he needed to know how far the drugs would stretch. What he's found is acceptable, but far from ideal. At Stark's current doses, they have five full weeks of morphine left; allowing for the way Stark's need will decrease as he heals, it'll be enough to see him through the recovery.

The trouble is that _all they have_ is the morphine: there are antibiotics, yes, and drugs for a few other purposes, but he has only the one analgesic. It's a powerful drug, and Yinsen was more than grateful for it when Stark was fresh from surgery and only the opiates could spare him from agony. They're two weeks out now, though, and continuing to use it as he heals is... not ideal. It will cloud his thinking and weaken his hands, even as he begins needing full use of both. If he hasn't hallucinated yet, he'll likely be spared that side effect, but the confusion and tremors will be quite bad enough once the Ten Rings _really_ begin demanding that he get back to work.

And there's always the specter of addiction. Yinsen does _not_ want to deal with morphine withdrawal in a place like this, especially without the risk of lethal complications to help him wring concessions from their captors. They would know that withdrawal can't kill Stark, so they'd probably take great pleasure in watching him writhe his way through the symptoms with no pharmaceutical relief.

Pain, delirium, and addiction: he faces a delicate balancing act between them, and the prize is Stark's sanity.

He sighs again and slips the scrawled inventory list into his kit. He'll do his best, of course. What other option is there?

\---

"I'm allowed to have plans on my birthday," Pepper tells him. She's walking backwards through the living room of his Malibu house, maneuvering flawlessly around the furniture as she has so many times when trying to make him sign something on the move. There's nothing in her hands this time, though, and he wonders disjointedly why she's bothering.

"It's your birthday?" he asks. He's already had this conversation. He knows her birthday. (He doesn't think he'll ever forget it again.) She nods at him, perfect eyebrows arched, and he stumbles over an ottoman. "I knew that. Already?"

"Yeah. Isn't that strange?" She tilts her head, accenting the resigned, amused, sardonic twist to her voice. Her heels are ridiculous. Stratospheric. The same vivid, burning red as her hair. "It's the same day as last year."

"Get yourself something nice from me." Why is he having this conversation again? Can he even get it right this time?

Pepper chuckles. The impossible shoes clatter on the stairs. "I already did."

"And?" Tony trips on his own feet. Only Pepper's quick hands keep him from tumbling head-over-heels down the stairs into his workshop.

"It was very nice." She turns, smiling up the last two steps at him. He freezes in place; that clear, genuine smile pierces him to the heart.

He chokes out a "Yeah?"

Elegant fingers tap Pepper's code into the workshop door; it slides open, and a mountain of white desert sand begins pouring through. He blinks at it dumbly, unable for a minute to get past _there's sand in my shop_ and _what the hell, JARVIS_. It falls, hissing, to pool around Pepper's ankles.

When he looks back up, there's an antipersonnel mine in her slender hands. "Very tasteful," she says, caressing its gunmetal surface, the viciously utilitarian shape of it. She smiles that same perfect, innocent smile as she presses the trigger plate and holds it. "Thank you, Mr. Stark."

Tony's frozen, his heart in his throat, the plans for that very mine flashing through his brain. _Hollow-core shrapnel, secondary charge shaped for maximum horizontal radius_ : all the specifications for lovingly crafted carnage. He croaks his last line through a closing throat. "You're welcome, Miss Po--"

She releases the trigger plate, and Tony wakes screaming.

\---

Stark wakes with a scream that echoes through the cell and jolts Yinsen right out of his chair. Even as the doctor recovers and races to his side, the man's all but convulsing in his cot, body trying to jackknife upwards but unable to manage it. His eyes roll in their sockets, wide rings of terrified white around black-blown pupils. "Pepper no!" he gasps.

Yinsen pins him, firm hands on his shoulders, and leans close to his face. "Stark! Stop it, you'll hurt yourself!"

His voice hits Stark like a physical blow. The man stills, quivering, and his eyes actually focus. Then Yinsen's presence must start to compute, because Stark goes limp with a dull groan, his fingers scrabbling against the canvas. There are fresh red spots soaking through his bandages.

"All right, Stark? Are you with me?"

That just gets him a choked _"fuck."_ Stark turns his head away, but not before Yinsen glimpses trails of moisture at the corners of his eyes. The doctor lets out a long breath. "You're all right, Stark." If his patient only gives him a raw, hysterical giggle... well, it's better than mindless terror, at least.

It takes Stark a long few minutes to stop shaking. He gulps harshly, then tries to laugh. "Anybody asks... that was th'morphine. M'not us'lly all..." He trails off with a vague gesture.

Yinsen only nods and hums noncommittally. The red blotches on the bandages have stopped spreading. He'll have to check the stitches --

Metal bangs, deafening in the brief silence. Voices clamor outside their door.

Yinsen leaps to his feet, terrified that Stark's scream has somehow drawn their captors' ire, but the men who clatter through the door aren't Abu Bakaar's or Raza's usual honor guard. It's just a few of the Ten Rings' foot soldiers -- he thinks he recognizes the Czech, Dusek -- and the way they warn him back from the door has a strangely perfunctory air to it. He doesn't question it aloud, since they are still waving guns at him, but curiosity simmers under his fear.

His puzzlement is answered a minute later, when four men stagger through the door, struggling between them to carry a battered old washing machine. They heave the clunky thing over to the workbenches, dropping it with a resounding crash next to the rest of Stark's assembled materials.

Yinsen risks a small, questioning noise.

"Delivery," one of the four replies, stretching his back and dusting off his hands. He jerks a careless thumb at Stark. "He asked for it. Materials, I guess. Abu Bakaar says he can get to work now."

Yinsen can only glance over at the thing, blinking in astonishment. When he looks back, the guards are already disappearing through the door; hollow metal booms shut behind them, locks click and rattle, and he's left in the fading echoes before he can figure out what just happened.

Stark echoes his thoughts, albeit with his own vulgar touch. "Th'hell just happn'd?" he asks the ceiling.

"They... brought you a washing machine," Yinsen replies, cautiously.

Stark laughs hard enough to tear two more stitches.

\---  
\------  
\---


	10. Synthesis

**Summary for the Chapter:**

> _Electronics manufacturing is, to be perfectly frank, nothing at all like surgery. The stiff, tidy sharpness of small electrical components, the unruly tangles of wiring ruthlessly straightened and laid out on benchtops, the smell of hot metal and offgassing plastic -- all of it is quite alien to Yinsen’s professional experience. He tries not to be insulted by Stark's apparent surprise when he solders the first connection perfectly anyway._

**Notes for the Chapter:**

> (synthesis: combination of components to build a product; combination of ideas to build a theory)
> 
> Betaed, as always, by my beloved writing buddies, fledisthatmusic and MountainRose.

Tony drifts up from a shallow sleep into the murmur of voices in an unfamiliar cadence. Yinsen’s tones, he recognizes immediately, but the doctor’s talking with someone he doesn’t know. The language is also strange — not the Arabic or Dari that he’s come to recognize, even if he can’t understand much yet. As his eyes drift open and the shadowed ceiling blurs into focus, he registers an even more interesting fact: neither voice is strained. He knows by now what their captors’ demands and Yinsen’s demurrals sound like, and this conversation is neither.

Almost as wary now as he is curious, he rolls his head towards the sounds. Yinsen’s standing near the cell doors, facing another man, a bulging canvas sack dangling from his hand. Tony can’t make out the other man’s face from here, but his voice is familiar. Something about that accent...

As Tony puzzles over that, the visitor holds out one hand demandingly. Yinsen obliges him, handing over the bulging bag. As it changes hands, Tony catches a faint whiff of something warm and fresh... was that _soap?_

No, not soap: laundry detergent. The man with the bag opens its drawstrings, pulling out something that looks _exactly_ like a gray tube sock. Patches on the heel and toe, even. He catches another breath of soap. Fresh laundry. What the hell?

Whatever the reason, the sock appears to satisfy their visitor: he drops it back in the bag and holds out his other hand to Yinsen, who grasps it for a brief, hesitant shake. The other man grins, saying something in that unfamiliar language, and shoves a small, dark package into Yinsen’s hands. Clapping the doctor on the shoulder, he turns and slips out of the cell before Yinsen can respond.

As the door booms shut behind him, Tony quickly closes his eyes and pretends to sleep.

“I know you’re awake, Stark.”

Busted. Tony cracks one eye open. At least Doc looks more amused than annoyed. “Laundry? R’lly?”

Yinsen shrugs, absently unwrapping the little package. “You aren’t using the machine yet, and he was willing to trade. Clean clothes for one of these.” He holds up his prize: a stubby, worn-looking shaving brush.

Tony’s eyebrows pop right up his forehead. “Oh, hey.”

Doc quirks a little smile. “Mm-hm. The better to do something about that beard of yours.”

 _Beard?_ Tony frowns. “S’a goatee.”

“Appropriate — it’s grown so ragged, you look like one of my sister’s goats.” He waggles the brush, and Tony’s not too indignant to admit that it’s tantalizing. “Let’s give you a trim, hmm?”

\---

Stark watches with anticipation as Yinsen begins to lay out the necessary tools. A bowl of hot water, a cake of soap, the new shaving brush, the shaving kit rolled up in its leather case... The doctor stifles a small smile. Stark hasn’t showered since his convoy was blown up; hasn’t even had their basin-and-washrag approximation of a bath since before his second surgery; and between the pain and the embarrassment, hasn’t exactly been requesting frequent sponge baths from Yinsen. A proper shave will doubtless go a long way towards making him feel human again. God knows it and a clean shirt have frequently been the last things keeping Yinsen sane in this hellhole.

When he unrolls the shaving kit, though, he becomes suddenly aware of a low, rhythmic sound that’s been growing below his notice. He glances up, curious, to see Stark drumming two fingers against the cot, perfectly in time with his pulse. The man’s eyes are riveted on Yinsen’s hand, which is resting on the straight razor.

 _Oh._ Curious, Yinsen shifts his fingers, sliding a the blade a few degrees free of its handle. Stark’s throat works, and his tapping speeds up.

“All right, Stark?”

Stark actually jumps, his eyes snapping up to Yinsen’s face. “What?” He swallows again. “M’fine.”

Yinsen raises his eyebrows and waits.

The dark head tilts away from him; Stark rolls his eyes. “You’ve cracked m’chest. Twice. Think I c’n trust y’with a razor to m’throat.”

The doctor chuckles, not ungently, and slides one arm under Stark’s shoulders. His patient helps a little, but it’s mostly Yinsen’s strength that gets him propped upright against the missile crate at the head of his cot. “If I wanted to kill you, Stark, you’d have been dead a month ago.” That doesn’t mean he’s unaffected by Stark’s trust. When Stark let him operate, there was no choice — once because he was half-dead and strapped to the operating table, once because he’d have been dying again unless they acted — but here? He could forego the shave if he truly feared it.

Besides, for all that Yinsen’s stuck tubes down this man’s throat and literally touched his beating heart, there is something uniquely and frighteningly intimate about lying conscious and still to let another person scrape a razor blade over one’s pulse. He can respect that. It turns this simple ablution into an act of trust.

For Stark’s sake, he won’t soon show it, but Yinsen is touched.

\---

“We should — sh’ld trade — languages.”

Doc just hums noncommittally. Tony’s pretty sure he isn’t paying attention. Well, fair enough — he’s a little distracted too, with the straight razor and all. He squints down at the blade lying on the benchtop in front of him, his limp fingers curved over it. Three days and two shaves after that first trim, he’s gotten used to the thing’s innocent lethality, but it looks like Yinsen still wants him to concentrate. “M’serious,” Tony insists. It’ll be another minute before he’s up to finishing; might as well make his proposal now, distract himself from his throbbing ribs. “Get me con— conversation’l in whatever — language’ll be most useful — down here, n’I’ll — get you writin’ — some Java.” Deep breath. Ow. “You’ll like it. Runs lotsa — a’medical systems. It’ll — come in handy.”

Yinsen raises an eyebrow at him. “Save your breath. You’re almost done.”

Tony rolls his eyes, but picks up the razor again and lifts it to his chin. He’s only got a few strokes left, which means he’s been doing this long enough to feel every movement _all_ the way down his chest. It also means that if he stops now, he’ll look pretty stupid with just the one patch of stubble left on his jaw. Doc already warned him — he’s got no compunctions about letting him run around like that for a few days, if it means he’ll be more motivated to finish his shave-and-PT. _Motivated,_ like Tony’s got no other reason to care. “Yeah, yeah,” he breathes, and drags the blade over his skin.

Doc must be feeling a little merciful after all: when Tony lowers the razor, he swoops in with a towel and mops the last of the soap off Tony’s chin. (Tony tries not to chafe. Yeah, he could have gotten that himself, but to be honest he kind of appreciates the break.) “Good work,” Yinsen observes, nodding meaningfully at the mirror.

Tony’s actually forced to agree with him. His stylist would probably commit seppuku if he ever gave Tony a trim this ragged, but under the circumstances... well, Tony’s happy to have anything even resembling his customary rakish Van Dyke. The new goatee molds around his half-smile. “Not bad, yeah. Steady hands.”

Yinsen snorts, not quite managing to hold back his smile. “You nicked yourself twice, Stark. I’m just happy you didn’t slit your throat.” He starts packing up the shaving kit. “Your range of motion’s improving, though. Keep doing this well, and we can have you handling a soldering iron in the next few days.”

Tony smirks at that. Suck it, tendon injury! He’s getting back to _work._

Speaking of, though... “So what d’you say?”

Doc blinks. “Well, you’re progressing faster than I’d expected —”

“No, th’ _language_ trade. We on?”

Doc considers for a moment, probably weighing the benefits of programming versus the pain in the ass of teaching Tony Stark. It takes him a while. “All right,” he drawls finally. “What languages do you speak now?”

Score one for Stark. “English, French, Italian, Pyth’n, Perl, Java, C++ —”

 _“Human_ languages.”

Oh, sure, cut off the bots. Machine languages totally count. “Just th’first three then.”

Doc cocks an eyebrow. “Not bad, for an American.” He continues before Tony can start defending his countrymen: “Dari, then. We’ll have to start from the alphabet, but you’ll find it useful throughout this country. It’s one of the few commonalities our hosts share.” He considers. “Most of them.”

Fair enough. Tony grins. “Deal. Get me that laptop — n’we can start anytime.”

\---

Electronics manufacturing is, to be perfectly frank, nothing at all like surgery. The stiff, tidy sharpness of small electrical components, the unruly tangles of wiring ruthlessly straightened and laid out on benchtops, the smell of hot metal and offgassing plastic — all of it is quite alien to Yinsen’s professional experience. The only common denominator is the need for a sharp eye and a steady hand, which was probably also the only reason he was able to pick it up as quickly as he did. He tries not to be insulted by Stark’s apparent surprise when he solders the first connection perfectly; it’s reasonable to think that a man might not succeed instantly at a brand-new skill. What the engineer’s apparently forgotten is that this skill is hardly new.

“I did watch you work on the housing,” he reminds Stark, smirking and gently patting the man’s back. “Besides, who do you think built that first electromagnet?”

Stark snorts, then winces. “Coulda told me that _b’fore_ I tried teaching you again.” He reaches out and takes the soldering iron from Yinsen’s fingers; the doctor lets him, pleased to watch him lift the hundred-gram tool with hardly a flinch. “Get going on these boards, then.”

Yinsen peers over Stark’s shoulder, at the collection of cannibalized chips, wires, and assorted bits and pieces. (That one’s a resistor, he thinks.) The drafts under the engineer’s hand are equally unintelligible. “You’ll have to set them up for me first.”

“Can’t read a circuit diagram?”

“Not like those, no.” In all honesty, he might be able to manage, if Stark explained how on earth he’s getting meaningful diagrams out of the loose stack of drawings at his right hand... but the fine-motor task of laying out each circuit board will be good for Stark’s fingers, and will probably keep his brain a little better occupied to boot.

Stark huffs a put-upon sigh, but puts the iron down and picks up a rough trapezoid of empty circuit-board. “Fine. Grab the rosin-core and th’silver solder — they’re over there somewhere.”

When he returns, laden with coils of soft metal, Stark is absorbed enough in his work for Yinsen to spend a moment observing him. He’s moving slowly — slower than he’d like, as his furrowed brow and little frustrated huffs make clear — and with a clipped economy quite unlike the unconscious grace Yinsen had seen as he built the reactor. He is moving, though, and freely enough to have apparently run a hand through his hair a few times. For all that his hands shake when he reaches too far over the benchtop, he’s already laid out one small circuit board and is working on another. He’ll keep a while longer.

Yinsen settles down next to him and proffers the solder.

The pair of them work their way through several components in fairly short order. As Stark passes them over to him, Yinsen solders salvaged missile chips and mismatched capacitors into place on mysteriously-shaped chunks of stripped-off circuit board. He burns his fingers more than once, touching a connection before it’s fully cooled, but says nothing.

When he finishes the fifth board and sets it aside, he looks up to see Stark trying to stretch out his shoulders. The cautious, wincing motion doesn’t seem to be helping very much. “Getting sore, Stark?”

“M’fine.” He drops his arms, still slow and careful. “That’s all the circuit boards — for now. Some wiring next.”

“Just show me what to do.”

Stark sends him off to fetch and carry again. This time, when Yinsen returns, the engineer’s still bent over his stack of drawings. The doctor unloads the coils of wire, fine plastic tubes, and arcane die-cut connectors, and then leans in to peer over his shoulder.

...Now he _knows_ Stark is leading him on.

“Stark?” The engineer meets his eyes, cocking an eyebrow, and he points at the topmost diagram. “Unless I am very badly mistaken, that is the drawing for the IV pump. Unless I am much worse mistaken, what we’ve been building for the last hour is _not_ an IV pump.”

That just gets him a smirk. “Good eyes.”

“Don’t condescend, it makes you look foolish. Are you even using those drawings?”

Stark sobers. The dark eyes flicker over Yinsen, head to toe, appraising something. “Yeah,” he says finally. “I am.” He hesitates a moment longer, fingers tapping on the benchtop. Then: “Want to see?”

\---

He hadn’t been using his entire set of drawings for the work at hand — no need for the leg-actuator designs when he’s trying to wire the upper torso and shoulder rotation — so Tony ends up having to enlist Yinsen’s help gathering the rest of them up. When the doc’s got them all together, the two of them get Tony out of his chair and onto his feet, which has been getting a lot easier lately. He hardly staggers at all as he leads Yinsen over to the nearest chunk of free workbench.

“So, all these drawings? Really only one thing.” The pages crackle as he lays them down on the sheet of glass that is their makeshift lightbox, reaching underneath to flick the little bulb into life. Yellow light filters up through his careful annotations. He doesn’t align them just yet. Sure, he trusts Yinsen, but this is a big step.

Doc picks up the first few sheets, frowning. He isn’t gonna see anything interesting that way — just a wind turbine and a PC cooling fan, with certain bits meticulously inked. Tony nudges his wrist, guiding the pages back down. “This is our ticket outta here,” he explains.

Doc flicks a glance his way, puzzled. Yellowish paper reflects in his glasses. “What is it?”

Yeah. Time to let him in on the secret. “Flatten ‘em out and look.”

With a smooth, certain gesture, Tony presses the sheets together. The graphite blurs through all the translucent pages, but ink is darker: even from the very bottom sheets, the inked fragments show through, and when the pages are arranged like this, they all align. Curves of a turbine blade, line of a gearshaft, machined edge of a heat-sink — it interlocks as perfectly on paper as it did in Tony’s head, and the Suit’s forbidding scowl rakes over them both.

Tony glances over at Yinsen, watching comprehension wash over his face. He resists a smirk and looks back at the drawings; in his peripheral vision, Doc’s lips curve into a slow smile. “Impressive,” he breathes.

Damn, that was satisfying to watch. Tony finally lets the corner of his mouth tick up. He’s on his feet. They’ve started the wiring. Doc knows the plan. Doc _likes_ the plan. It’s time to start building this thing for real. And when it’s ready...

Cool, thrumming anticipation coils somewhere under the reactor housing. Those bastards will never know what hit them.

\---  
\------  
\---


	11. Relapse

**Summary for the Chapter:**

> _I -- am going -- to_ live.

**Notes for the Chapter:**

> (relapse: a sudden decline in a patient's condition)
> 
> I'd apologize for this chapter if I actually regretted it.
> 
> Betaed by the indispensable [fledisthatmusic](http://archiveofourown.org/users/fledisthatmusic/pseuds/fledisthatmusic) and [MountainRose](http://archiveofourown.org/users/mountainrose/pseuds/mountainrose), now with interjections by [szzzt](http://archiveofourown.org/users/szzzt/pseuds/szzzt).

The scars aren’t as bad as Tony’d expected.

Shrapnel wounds _hurt,_ okay? Maybe he hadn’t felt anything at _first,_ lying flat in the sand with the air and the arrogance both blasted out of him; his brain had been too busy spinning with the shock of being blown up by his own rocket. His hands had pretty much gone on autopilot, ripping at his shirt under their own power. When he saw the blood pumping through his body armor, though -- _that was an H12 Tack there’s shrapnel in my chest oh god I’m bleeding out_ \-- yeah, _then_ it had hit him, like red-hot spears tearing through his flesh. Pain like that, he'd expected to find half his skin ripped off.

But either the barbs hadn’t shredded him as badly as he’d felt, or Yinsen’s just that good, because all that’s left from _that_ little slice of hell is a constellation of sliver-thin cuts across his upper chest. Each one’s barely half an inch long, still pink and raw but already fading. When they’re all healed up, it’ll hardly even show.

He doesn’t think he’ll be so lucky with the surgical scarring. A lot of it is bunched up around the edges of the reactor housing, fading into the background against the distraction of bright titanium, but there’s still a long puckered rope twisting down his midline from the bottom of the thing and disappearing into the bandages that Yinsen’s still unwinding. The herringbone marks of small, even stitches are still visible holding it together.

“So when do these come out?” he hears himself ask, tapping at the stitches (and _ow,_ he’s got to get that tic under control; there are way too many bits of him that just don’t appreciate being poked right now).

“The sutures will dissolve in place.” Yinsen glances up from unwinding the last few layers of gauze. “Catgut’s crude, but it has its advantages.”

Catgut? Tony decides he probably doesn’t want to know.

Yinsen finishes with the dressings, bundling them away to reveal the full length of the scar. It’s... well... “Christ,” Tony mumbles, drawing one knee up to watch it twist, “what’d you do, saw my whole _sternum_ in half?”

“Yes, actually.”

...Can’t really argue with that. Tony runs his fingers lightly along the scar, just to one side of the tender new skin, and lets his head drop back to the pillow. It’s not like anyone who matters will think less of him for it. As for the people who don’t matter so much... hey, they say chicks dig scars, and now he can find out for sure.

Seriously. Who is he kidding, fixating on that?

_Be honest with yourself, Stark._ It’s not pretty. _He’s_ not so pretty anymore. It’s going to turn people off, maybe even drive them away, if the nightlight in his chest doesn’t do it first. Some of them might have the opposite reaction, but he’s got no way to tell. This is going to be a pain in the ass. At least he’s got the option of covering it up.

It and the reactor -- because like hell is he letting _that_ secret out, what with all the damage the wrong kind of people could do with miniaturized, controlled cold fusion. He watches the circle of blue light play across the rough stone ceiling, unmuffled by gauze for the first time since he installed it. That’s gonna be a little harder to hide. He’ll have to layer up if he wants to block it out completely.

No more shirtless GQ covers... it’s a pretty small price to pay for getting out of here alive.

Yinsen leans over him, drawing him back out of his reverie. Gentle fingers check the sutures again. “There you are. It’s healing well. Want to test it?”

Tony cocks an eyebrow at him. In answer, Doc wipes the sweat off his forehead and steps back from the cot, giving Tony a challenging stare. Tony’s had enough PT by now to be intimately familiar with _that_ look.

So he lifts his head, shifts his weight, and rolls his legs off the cot. Propped up on pillows as he is, it’s not hard to get himself sitting up. The cell looks different somehow; it takes him a moment to realize that the strange pallid cast is from the arc-light, and then he can’t help another glance down at the device still thrumming warm and quiet in his breastbone.

Yinsen’s still there when he looks back up, waiting for him, and Tony surges to his feet. God, he’s got his _balance_ back. He never thought it’d feel this good just walking, one jaunty foot in front of the other, a little of his customary swagger coming back from the sheer simple joy of independence.

He owes this doc _so much._

\---

When Stark gets off the cot and walks toward him, one hand outstretched, Yinsen’s too busy focusing on his gait to recognize the gesture. _Very steady, that’s good, though_ he’d _probably make a stagger look deliberate_ \-- and then he realizes that the man isn’t asking for support. That’s...

Startled into numbness, he can only reply in kind, clasping the strong hand in his. Stark’s eyes crinkle at the corners with gratitude.

The man lets go after a moment, though, breaking off from Yinsen’s path to make a beeline for their stack of clean laundry. “I get a shirt now, right? I’ve about had it with the bandages, it’s been way too long since I had real clothes.”

“Something light,” Yinsen warns, but he can’t stop himself from smiling. “The scar tissue is still tender.”

“Yeah, yeah.” Stark’s already shrugging into a too-large button-down, rough linen gone gray from a thousand washings. “I can take it. C’mon, it’s just a shirt.”

Yinsen should probably protest: the dressings have come off, but that doesn’t mean Stark is invincible. He suspects his patient knows, though, and he himself is still working through the shock. Such a simple gesture, and it’s all but knocked him off his feet. He should know better, but... well...

It’s just been so very long since anyone thanked Yinsen for his work.

\---

_“Dsta bala!”_

Hey, Tony actually got that. _Hands up,_ they said. His Dari’s improving --

\-- right, _hands up,_ as in “get your hands over your head _now_ because we’re about to barge in and jab you with guns.” Tony fumbles the last shirt button and hauls himself to his feet as fast as he can, shoving his hands behind his head and only wincing a little when his sternum creaks. S’okay, he’s just had his morphine; they can deal with the rest when Beardy isn’t threatening to redefine “excessive force.”

The door booms open and yep, Tony was right, there’s the big jackass himself, all raggedy cloth and black hair... and he’s doing the eyebrow thing again. Shit. What’d they do this time?

Then Beardy’s survey of the room locks hard on Tony’s chest, and the big guy barks a torrent of angry, idiomatic Dari at Yinsen. Tony only gets a few words of it. _Not asked for, light_ or maybe _lamp,_ something _working_ something... Beardy thinks they’ve been working behind his back.

Well, they kinda _have,_ but that’s beside the point.

Yinsen stammers a reply. _It’s only his..._ that last one was _pacemaker,_ probably... _nothing to worry about._

Beardy lumbers over to Tony, yanking his shirt aside to squint into the arc reactor’s glow. Tony holds his breath. The guy smells like wood smoke and six days without showering, and there’s a Stark Industries SMG on his belt. Tony can’t restrain a flinch when Beardy jabs a rough finger square in the middle of the reactor. Beardy chuckles at that. This is not good. Tony braces himself: it can only get worse...

But Beardy just steps back and claps Tony companionably on the shoulder. Tony staggers and barely manages to catch himself, vision whiting out with the force of the blow. When he can see again, Beardy’s still practically leaning on his shoulder, grinning at Yinsen and saying something expansive...

_He’s much better already, I see. You have done..._ was that _good work?_ Really?

Yinsen’s reply is warily affirmative. Beardy squeezes Tony’s shoulder; Tony resolutely does _not_ let himself choke on the pain. _This is good. You can get back to work now, and in half..._ uh... _half the expected time,_ maybe? _I’m very happy with you,_ something-that’s-probably-a-title.

...Oh, shit. Tony does not like that grin at all.

Beardy finally lets Tony go, heading for the door. Before he leaves, though, he snaps something to a couple of lackeys, who make straight for Yinsen’s kit. Even blinking spots out of his eyes, Tony can hear the doctor’s terrified protests.

But the big terrorist just keeps smiling, and for once Tony can understand him perfectly. _Now we can use this on the ones who really need it._

The door bangs shut again, and Tony lets himself drop back to the cot, breathing a heartfelt string of profanity. “What just happened?”

When Yinsen doesn’t answer, Tony looks up. Doc’s standing frozen, right where Beardy left him. “Doc? You okay?”

The doctor shuts his eyes, drops his arms, and plods over to Tony. “Fine, Stark. I’m fine.”

“Yeah, ‘cause that’s _just_ what fine looks like.”

Yinsen picks up Tony’s wrist. There’s a fine tremor running through the fingers that he presses to the engineer’s pulse. For a long moment he’s silent; then he exhales, very slowly, and bows his head. “I’m sorry, Stark. They took the painkillers.”

Oh, _shit._

\---

Seven hours later, the morphine has worn off.

Stark doesn’t complain aloud, but Yinsen isn’t blind. He knew as soon as Stark put his work aside and laid down on the cot of his own volition. He can see it in the clench of the man’s fists, the sweat glimmering on his forehead, the way he holds his body rigid against the canvas. He can hear it in his shallow, uneven panting and the groans that he tries to bite back.

It’s only been seven hours. The withdrawal itself hasn’t even begun yet.

“Doc.” Stark shifts on the cot, dragging one heel across the canvas. His skin is ashen, his voice thin and thready. “Talk -- talk t’me. How bad’s it g-- gonna be?”

“Save your breath,” Yinsen warns him, but brushes the hair back from where it’s sticking to his brow. “You shouldn’t worry about that.”

“Gonna -- happen anyway. What sh-- sh’ld I ex--” and he draws a sharp, hitching gasp -- “expect?”

The doctor looks him over. At very least, he needs a distraction. Taking away the drugs is cruel in more ways than one: the morphine had not only made Stark’s pain bearable and eased his breathlessness directly, but also clouded his mind. Now, not only is he deprived of physical relief, but the man’s whole genius intellect is free to dread the coming agonies. “Let me worry about the details. You won’t be feeling talkative after the first twenty-four hours or so. Is there anything we should wrap up before then?”

“Twenty-four _hours?”_ Stark lifts his head, alarmed. “How l-- long is this gonna -- be?”

Curse the man’s tenacity. Yinsen is trying to _help._ “Seventy-two hours is typical. You, of course, never do anything the easy way.” Stark flinches. “Which may mean a shorter course or a longer one. I have no way to know.”

“God.” Stark lets his head drop, flinching again at the impact with his pillow.

“So I’ll ask again. Should we--”

“--wrap up, yeah.” The dark head turns toward Yinsen. “Could f-- finish th’ sec’ndary m-- myoel-- electric algorithm.” He pauses, closing his eyes, and swallows hard. “Uh. _You_ could. I’m not -- not goin’ a-- anywhere.”

“It’s temporary--”

Stark snorts, then visibly regrets it. One heel digs into the canvas again, his head tossing. When the tremors subside, he slits his eyes open to stare at the doctor. “Don’t k-- kid me. S’gonna be w-- weeks before -- I can st-- stand again, isn't it?”

“You know, the more you focus on this, the more it will bother you.”

Unfortunately, Stark is intelligent enough to hear the _probably, yes_ behind Yinsen’s evasion. His eyes slam shut as he turns away again; his hands on the cot clench into fists. What should have been a snarl comes out instead as a sob.

Yinsen bows his head in silence. What can he say to this? Yes, Stark faces a serious setback. Withdrawal and pain will weaken him, probably push him back two weeks or more. Two weeks ago, the man couldn’t even sit up unaided. How will he bear being forced back to that?

Worse, how will he bear having to do it all again? Stark fought and clawed for every inch he’s losing. He was recovering far faster than Yinsen had expected, and the doctor had chalked that up to his iron will. The way he’d driven himself through the exercises, kept working through the pain -- a lesser man would have faltered long before.

No... actually, a lesser man would have given up before any of this began.

A lesser man would have crumbled under torture. A lesser man would have shattered at the sight of his magnum opus aimed at innocents. A lesser man certainly never could have built a new, impossible heart to shore up the one the Ten Rings tore open. Stark’s indomitable will is the only reason he’s still alive.

Something cold blossoms slowly in Yinsen’s gut. Stark stood up today, and then Bakaar slammed his legs out from under him. Less devastating blows have shattered the strongest people Yinsen’s known. If this breaks him...

Once Stark’s gone, the Ten Rings will have no use for Yinsen, and honestly... neither will he.

\---

T plus fourteen hours, and Tony feels like hell.

It apparently isn’t enough that without the drugs, his chest is one solid mass of searing pain. No, biology’s a sadistic bitch, because the withdrawal symptoms are setting in even faster and harder than Yinsen expected. Arctic chills switch off with hot flashes (what is he, menopausal?); his body’s dumping water in every way it can; he aches bone-deep even where he’s not on fire; and worst of all, he can’t even lie still. His muscles won’t quit _twitching,_ and every little jerk just rattles all the way through him. Withdrawal won’t even do him the courtesy of letting him pass out, never mind that he’s exhausted like he’s never known before; he is acutely, torturously aware of _absolutely everything_ that so much as brushes past his senses.

Including the sudden metallic clatter that explodes against his skull like a grenade.

A really undignified noise leaks out of him, but he’s too busy curling in on himself to care. (Can’t even clutch at his head, because moving his arms has gone right back into _no fucking way_ territory.) “Dummy!” he gasps, clamping his eyes shut. Clumsy damn bot, never knows when to shut up -- “Corner, y-- y’stupid -- jus’ _go_ \--”

“Stark?”

His eyes snap open, and even before he blinks all the crud out of them he can tell that the face leaning over him does not belong on the end of an arm. For way too long he stares up at it, mute and stupid with misery. When recognition finally hits him -- _Yinsen cave humvee magnet Rings_ guns _oh fuck_ \-- it’s all he can do to keep from sobbing.

“Not you,” he chokes out instead. “Thought -- some’n else...”

“I had wondered.” There’s a thread of amusement under the careworn weight of Yinsen’s voice. “You have said strange things in your delirium, but insulting me? That would be new.”

“N-- not dumb ‘nough -- t’diss th-- th’guy with -- th’needles.”

Yinsen chuckles quietly. A cool cloth touches Tony’s face, wiping away the fluids streaming from his eyes and nose. He jolts at first, surprised, but it’s kind of soothing once he gets over the extra shock of pain from jarring his ribs. “Call me whatever you like, Stark.” The cloth pauses minutely, and the voice grows somber. “Only keep talking. Stay with me.”

Tony doesn’t dignify that with a response. He isn’t going anywhere like this, and they both know it.

\---

It has been twenty hours now, and Stark is in agony. He lies shivering in the unforgiving cot, soaked in sweat, wracked by ceaseless muscle spasms and vicious stomach cramps. Dehydrated as he is -- he can’t keep anything down for long, not even water -- his eyes and nose still dribble constantly. He lost the fight to keep silent hours ago, and every shallow breath is a quiet whimper.

Yinsen tends him as best he can, but it isn’t much; the last of the muscle relaxants wore off two hours ago, and they’ve been out of oxygen for days. Instead, he resorts to nursing duty. He changes Stark’s rough bedding; he wipes away the involuntary tears; he coaxes a little water down his patient’s throat, to stave off the sheer dehydration that could still kill him before this is over. When a particularly bad spasm wrenches through Stark, Yinsen grips his shaking hands, restraining him against the impulse to claw at his wounds in mindless anguish. It’s all he can do, and it hasn’t been enough.

Under Yinsen’s hands, Stark spasms and chokes for the hundredth time. His body jerks against the cot as another cramp sinks its claws into his belly; blind instinct is trying to curl him up around the pain, but the movements abort quickly when they start to jar his ribs. He doesn’t even have the strength to clutch Yinsen’s pillow close, where it would more effectively support his chest. Instead, the doctor leans in to help him, hands pressing down gently over the pillow, holding him together while the spasms tear through him. Stark’s fingernails rake helplessly down the canvas.

It takes a long time for the fit to pass, but finally Stark’s body goes still for a moment. His wire-taut muscles relax a little. The breath jolts out of him in a feeble sob that catches in his lungs, turning into a wet wrenching cough.

“All right,” Yinsen soothes, maintaining the gentle pressure. The pillow is all he can give Stark to support the damaged ribs, and he fears it won’t be enough. With four weeks of healing behind them, the bones have knitted more than halfway... but they haven’t finished, the callus tissue still fragile, and these convulsions run a very real risk of re-breaking them. The last time he used his stethoscope, Yinsen had heard Stark’s sternum creaking with every jolt.

Morphine withdrawal is bad enough in healthy patients. Yinsen shies away from contemplating how Stark must feel right now.

This is torture, as sure as the dunkings were and just as cruel; the only difference is that this time there are no questions. Stark already agreed to their demands. This can only be for Abu Bakaar’s amusement. Yinsen wishes the bastard in hell with an ardor that surprises him -- he’d thought it reserved for the murderers of children.

For murderers like Stark.

Yinsen’s hands, suddenly nerveless, drop from the pillow. He is incensed on _Stark’s_ behalf. The man whose weapons killed his family, the man who only weeks ago he tended out of disgusted duty, and now his protective rage smolders just the same for the Merchant of Death as for Fahran and Aliyah and _Mehri,_ his Mehri --

He stumbles up and back from Stark’s cot, his feet catching on the box where he sat. His gorge rises. For a searing moment he’s not in the cave anymore, not at a sick man’s bedside, instead there’s broken tile under his feet and his hands are torn from digging through rubble and his throat is sore from screaming and all he can smell is smoke, gunpowder, a horrible clean reek of ozone, burning hair -- burning --

He comes back to himself sprawled gracelessly on the floor, his back against the leg of a workbench, hands trying to push himself past the obstruction. His sobs and Stark’s mingle.

...Stark. Another spasm ripples down the man’s spine, all the clearer to see from this low angle. With no hands there to hold the pillow down, the awful creak of overstressed bone actually carries across the cell.

Yinsen is up and back at the bedside before he’s fully aware of moving. Dazed, he watches his well-trained hands pull Stark back together. What is he doing? Why, why would he care for the Merchant of Death, why tend _him_ as he would his own murdered children? Stark brought this on himself!

But he’s still Yinsen’s patient. He’s a man, flesh and blood, and he is suffering. The Merchant of Death, that grinning jackal, he cannot suffer. He cannot run a fever, or struggle just to breathe through his pain. He has no fragile heart to flutter at a surgeon’s fingertips.

Nor would the Merchant of Death have blanched when he saw the Ten Rings’ weapons stockpile. He would have delighted in that amassed, patient cruelty, not stared it down and turned away. _He_ never would have chosen to change.

_Tony Stark_ did. And Yinsen is a doctor: he does not countenance suffering while there is any other choice.

Calmed by the epiphany, Yinsen settles back onto his box, resting his hands on the pillow while his shudders subside. Just in time, too, it seems; Stark spasms again with a choking wheeze, his legs jerking involuntarily, and thumps his head weakly back against the cot. The wheeze doesn’t stop when his legs still, though, turning instead to a hacking, liquid cough. 

Suddenly concerned, Yinsen waits only until the choking subsides before picking up his stethoscope again. Stark shouldn’t be _coughing,_ not from morphine withdrawal. He dearly hopes that he’s wrong, but...

...no, there it is. It’s never been loud, and it’s almost hidden now beneath the groan of overstressed bones, but the sound is unmistakable. Stark’s lungs crackle with each tortured breath, in and out. Pneumonia, again -- a relapse. When Stark had fought it off the first time, Yinsen had been relieved by the lack of complications. He should have known the man would not be so lucky.

\---

There’s no _air!_

Jesus _fuck,_ he said _yes,_ why are they --

\-- not drowning this time -- his eyes are open and there’s nothing there, no green corpse-light and no Barrel, one face and not a dozen. Instead it’s some gigantic weight, an engine block perched on his chest, _crushing_ him --

\-- no, not even crushing, because his chest is heaving uselessly -- ribs creak and groan with the pressure, and it’s all helpless, breathless, but they are moving. He couldn’t do that with a car sitting on him. Doesn’t have the strength to lift a finger, sure as hell couldn’t lift a car --

\-- but then hands on his shoulders, an awful stab of vertigo -- he chokes as something shifts inside him, wet and flaccid as a dead thing tugged by the tide, to let a skinny breath whistle in. _Air,_ it’s nectar and acid on his ravaged throat; he hacks it back out in a horrible gurgling cough. Bone grinds with a noise like old timbers in the wind, and he loses the next wheeze on a voiceless sob. Someone calls out -- a name? His name?

The next breath, for all that he doesn’t have to drag it past the rotting flotsam anymore, is no easier. He can get air now, yeah, but that means _breathing_ \-- means making his creaking ribs and spasming muscles bow outward, means making them pull on all the wires and screws and desperate hopes holding him together -- oh _fuck!_ \-- and it’s not even worth it, not when his lungs are full of water and he can’t, he can’t --

He’s not sure how many breaths he loses that way, to helpless gasps and moans, before he can scrabble together some kind of control. The urge to breathe is powerful, but the pain is _so much worse._ This time, when the air hisses out of his constricted throat, he doesn’t draw it back in.

His chest falls still, flesh and bone lying supported by the metal instead of fighting it. No bloom of agony. No creaking grind. Still cold, still hurts, still something leaking down his face, but... he can... he can rest a little. Just a minute. Please, let him rest, just for a moment...

“-- do _not_ make me intubate you, Stark, you’d regret it --”

Splash of ice on his throat, and he chokes, gasps -- ribs laid open, chest torn through -- loses the air on another helpless cry. His eyelids twitch, and even _that_ hurts. _Damn you,_ he thinks, not even sure who he’s talking to anymore, _damn you, let me rest! Let me..._

...what? Let him stop breathing? Let him _die?_

_Like hell!_

He drags in another shattering breath, loses it to a hiss, and -- fuck everything -- _he does it again._ This will not end him. He won’t let it. He’s done too much, planned too much, too much left to do --

_Not here._

_Not like this._

_I -- am going -- to_ live.

\---  
\------  
\---


	12. Ductility

**Summary for the Chapter:**

> _He shrugs one shoulder, a gesture eloquent in its minimalism. “A useless doctor for a useless patient. Neither of us would live out the week.”_

**Notes for the Chapter:**

> (ductility: the ability of a material to bend with applied force rather than breaking)
> 
> My apologies for the really incredible delay on this one. Summer is _incredibly busy_ in my line of work, and I got next to no writing done for a few months while I traipsed around in the field. Good times, but not good for ficcing. ;)
> 
> I reiterate: _this fic is not abandoned._ I will tell you guys, explicitly and up-front, if I stop actively working on it before it's finished.
> 
> Piles of thanks go to my betas, [MountainRose](http://archiveofourown.org/users/MountainRose/pseuds/MountainRose), [Szzzt](http://archiveofourown.org/users/szzzt/pseuds/szzzt), and [keroseneSteve](http://archiveofourown.org/users/keroseneSteve/pseuds/keroseneSteve). I have no idea how I could ever write a monster like this without your help. <3

Three days in, Stark finally falls asleep. It takes Yinsen a few minutes to notice; for all that withdrawal has kept the man excruciatingly awake the whole time, hypoxia and delirium have had him drifting in and out of lucidity. The doctor’s caught no more than catnaps himself, dozing when he can between Stark’s more violent episodes.

When he realizes that the man’s eyes have finally closed, then, he blinks at them stupidly for a moment before the message gets through. When it does, he springs into a flurry of worried vitals-checking. Stark is more or less breathing, heartbeat as close to normal as can be expected, but the twitching has slowed and his nose has stopped running.

The withdrawal is over.

Yinsen’s breath whooshes out of him; he folds down to rest his head on the tangled blanket by Stark’s elbow. _Dear God,_ he thinks, and no one can possibly blame him if the laughter bubbling out of his throat is a little hysterical. _Finally._

When he can straighten up again, he clears his throat (winces as it echoes a rattling breath from the man on the cot) and shakes himself. This is no time to fall apart. Stark isn’t safe yet; he’s survived withdrawal, but he still must fight off infection. Again. Yinsen hefts his protesting bones off the box, moving around the cot to prepare. Refresh the blankets, clean Stark’s face, change the cold compress on his brow. Now that the spasms are past and Stark won’t pull it out, Yinsen places an IV; the two failed jabs, where he had to search for dehydration-withered veins, are worth it for the fluids and antibiotics his patient so desperately needs.

Never mind that he’s no longer quite certain the Rings will provide them. He’ll burn that bridge when he comes to it.

Last of all, he shuffles across to drag his own cot over beside Stark’s. There’s still work to come, and he’s lucid enough to recognize that he’ll be no good for it if he doesn’t rest a little. He can sleep like this, with one arm thrown over Stark’s stomach to wake him if his patient shifts. It’ll be enough.

His head hits the pillow, and he has just enough left in him to register the irritating scratch of his stubble on the covers -- _I need to shave_ \-- before he’s gone.

\---

Tony feels a hell of a lot better than he did yesterday. That’s enough for now. He’s okay.

Yeah... he’ll keep telling himself that.

It’s true, though -- he does feel better than yesterday. Amazing how he didn’t quite realize, not til they finally, mercifully stopped, just how badly those twitches were hurting him. Or how annoying it was to have his face constantly wet. Or -- yeah. That. He’s over all of that crap. Problem is, getting over withdrawal didn’t un-break his ribs. It didn’t get the crud out of his lungs, or cool his fever down. He still can’t _breathe_ right; bone creaks when he tries, and the rattling breaths don’t seem to contain much oxygen at all.

Verdict: “better than yesterday” is _in no way_ synonymous with “good”.

So he’s still lying mostly-immobile in the cot, panting shallowly for breath and trying not to groan too much, when the door to their cell... doesn’t _bang_ open, exactly. It more clunks open. Maybe _thuds._ Whatever the onomatopoeion, it’s seriously subdued compared to the usual belligerent clangor. Weirder still, there’s hardly any yelling. When Beardy comes through, it’s with barely half his usual guard, and he glares at them _silently;_ he turns to stare at each of them in turn, and Tony can just make out that his left eye is sunk in a purple smudge.

And then, to put the weirdness icing on this whole what-the-fuck cake, he thrusts a cardboard box into Yinsen’s hands. _Here,_ he growls. _Take it._

Glass vials rattle softly as Yinsen accepts the package. Whatever’s inside, it startles him into drawing a sharp breath. _Thank you,_ he murmurs.

Beardy turns and stomps back out, his guard slinking off behind him. The door clunks shut again.

Yinsen giggles.

It’s really the only word that applies to that kind of high-pitched, hysterical laughter. Doc’s knuckles go white where they grip the box. For a moment he sways in place; then he swallows hard, gulping the giggles back down, and staggers back over to Tony’s cot. He sets the package down on the workbench with incongruous care before slumping onto his box and burying his face in his hands. Tony still can’t really turn his head, but he watches the guy warily from the corner of his eye. “Doc?” he wheezes.

Yinsen shakes his head. “Irony, Stark. Just irony,” he sighs, and lifts the box over Tony’s face. It takes him a moment, what with the doc’s hands still quivering a little, but Tony finally manages to make out the label. _Morphine._

His brain grinds to a halt, shifting from fifth gear straight into reverse, and its engine falls out on the pavement. For about a year he can only stare at the box, wide-eyed and completely blank with shock. 

“What th’ _fuck,”_ he finally manages. “Why...?”

“Perhaps our esteemed host disapproved.” Yinsen shrugs wearily, putting the box down. “Raza wants you to work. This was hardly conducive to productivity.”

“Would ex-- explain -- the shiner,” Tony agrees. Inane, but his brain’s running in too many directions at once for useful conversation. He stares at the ceiling for what feels like a long time. What the actual _fuck._

Then he catches a flash of movement above him and turns his head to -- wait, what, _no._ Can’t actually grab Yinsen’s wrist, but his hand twitches up off the cot all the same. “The hell!” he yelps.

Yinsen freezes, lowering the syringe he’d been about to inject into Tony’s IV. “It’s only morphine, Stark.”

“Y-- yeah, I fi-- figured!” He glares. “Don’t.”

The doc’s eyebrows do something complicated and expressive. Tony doesn’t bother untangling the emotion there. “You need it, Stark. It’ll let you rest.”

“Not -- not _that_ way.” Tony can’t take his eyes off the syringe and its colorless contents. It’s still a lot closer to his IV than he’d like.

“Stark --”

“No,” Tony rasps, clenching his fists. “I just got _free_ \-- of that stuff. Three days -- of _hell._ Not gonna -- not doin’ it a-- again.”

Because he won’t lie and say he doesn’t want it, that just the sight of the thing isn’t waking a dormant craving. Won’t say he doesn’t hurt, that the offer of relief isn’t making traitorous heat prickle at the corners of his eyes. Thing is, though, that syringe isn’t just full of relief -- it’s full of _dependence,_ of the helpless need that he just paid off with seventy-two hours of agony. He’s free of it now, but if he takes another shot, the Ten Rings will be able to bridle him with it -- yank him around with just the _threat_ of taking the drugs away again, knowing damn well that a Round Two would break him once and for all.

Beardy can fuck right off. He isn’t going to _touch_ the morphine.

“There will be no need.” Yinsen’s free hand covers his, warm and grounding. He has to fight the impulse to relax -- the argument’s not over, dammit. “No one leaves my care addicted to opiates. We’ll taper down the dose as you heal.”

“Like you d-- did last -- time?” The doctor’s flinch absolutely does _not_ make him regret that. He’s making a point. “Th’bastards might -- not _let_ you. M’good. Put it a-- _away.”_

Doc shakes his head. “You need it,” he repeats, “and not just for sleep; you aren’t breathing right. To fight off pneumonia, you must breathe as deeply as you can.” He flicks a glance at Tony’s chest, heaving fast and shallow with what little breath he can steal. “You can’t handle breathing exercises if you can’t handle breathing normally.”

_You want deep breaths? I can do deep breaths._ Tony lets his air hiss out as slowly and evenly as he can. Okay. Now back in. Slow and even, and keep going even when it pulls -- oh _shit --_

“Stark!” Yinsen’s voice cuts through the rattling cough. “Easy. Don’t --” and his hearing goes again. Jesus, it’s been _how_ many weeks now? Shouldn’t he have stopped _feeling the bones grind_ yet?

When he can open his eyes again, he’s looking straight up at Yinsen; Doc is pressing a pillow down on Tony’s chest with both hands, the gentle, even pressure seemingly all that’s holding his ribs together. Tony’s gasps shudder right up through Doc’s elbows, the tremors visible even to his own pain-blurred eyes. “Shit,” he wheezes.

Yinsen sighs. The pillow vanishes. “You’re a fool, Stark.” He turns away, and glass clinks faintly in his wake.

Tony snatches one deeper breath, holds it for a three count, lets it shudder out. Does it again. The pain’s ebbing as he gets his breathing back under control; he relaxes back into the cot. Somewhere over his shoulder, Yinsen moves around; clinks of glass, plastic on plastic, plastic on wood. Weird, how those sounds have become sort of comforting. Doc’s in the house, everything’s quiet. He’s okay. Just try to breathe. His forefinger taps a heartbeat on the taut-stretched canvas.

...The pain’s ebbing, and Doc moved away. Caught by a nasty suspicion, Tony tries to lift a hand. It pulls, it aches, but it does rise. He lets it drop, twisting his head in sheer disbelief.

“Did you -- _dose_ me?!”

Yinsen pauses in his tidying, looking back over his shoulder. “Yes.”

“What part -- of -- of _no_ \-- didn’t you get?” Tony snarls. Tries to snarl. It comes out as more of a gurgle, but still works a lot better than it should. Now that he knows for sure, he can definitely feel it, the loopy warmth of the drug in his veins.

“The part where you tried to refuse the only possible treatment for a potentially lethal condition,” Yinsen tells him mildly. Bastard doesn’t even have the decency to look abashed.

“Not th’point!” Tony rolls a little to the side, the better to skewer Doc on his eyeballs. A brief spike of pleasure at the newfound mobility vanishes like smoke when he reminds himself _why_ he can suddenly move. “Told you no, goddammit. _Meant_ it.”

Because that’s the crux, isn’t it? _No means no._ Every damn person in this cave seems bent on doing things to Tony without his consent. Shrapnel in his chest, rough hands on his shoulders, scalpels and bone-saws, the water (the _water)_ \-- it’s his body, and they keep changing it without his consent. All of them.

All but one. He hadn’t consented to have that first electromagnet put in (admittedly, there hadn’t been much of a choice), but after that, Yinsen never did anything big without Tony’s permission. Manhandled him a little, sure, but mostly when he was actively dying; first aid hardly counts. This is different. This was considered, calculated. Tony said no, and Yinsen drugged him anyway. The one person in here he thought he could trust, and now...

“If you die, they will kill me too, you know.”

The quiet pronouncement startles Tony out of his thoughts. It doesn’t actually _surprise_ him, though. “Wasn’t gonna _die.”_

_“Perhaps_ not, but you would certainly decline. They would grow impatient.” Doc’s gaze is steady, his eyes dark. That he can be so matter-of-fact about their captors’ impatience, as if that doesn’t lead to stuff neither of them wants to contemplate, speaks to a hell of a history here. “I have already crippled you for weeks. If I allow you to refuse the only thing that lets you work...” He shrugs one shoulder, a gesture eloquent in its minimalism. “A useless doctor for a useless patient. Neither of us would live out the week.”

And Tony can imagine, all too well, how they would die. He can actually feel his pupils dilate, his vision going watery and too bright. His heart thumps once, twice, against the back of the housing, before he can calm himself enough to stop feeling it. That’s calm enough to protest, though: _“Crippled_ me? You saved my life.”

“Will they see it that way?”

...Tony can’t really argue with that, can he? He closes his eyes, defeated. “All right. You win.”

A warm hand wraps around his shoulder. “So do you, Stark.”

Tony drags in a shallow, whistling breath, torn between relief and simmering annoyance when it doesn’t hurt. The whistle and gurgle, though... “Still can’t breathe.”

“I know.” A shadow settles on Doc’s face; he looks away. “Analgesia is only part of the treatment you need, but they’ve refused to replenish my oxygen supply.”

Tony blinks. “Oxygen?” At Yinsen’s nod, he feels his lips quirk in a sly, savage grin. “Shoulda said something, D--Doc. _That_ one, we can fix.”

\---

Why didn’t Yinsen think of this himself? The cistern in the corner of their cave provides plenty of water -- more than they’ve ever needed, to be sure -- and the arc reactor provides plenty of electricity. Using electrolysis to produce oxygen is perhaps the single simplest idea Stark has come up with since Yinsen’s known him.

Even the device they’ve cobbled together to do it is uncomplicated. Bare metal plates of a certain size, dangling in a barrel of water, will connect to the reactor with two lengths of heavy insulated wire. When the circuit is completed, one electrode will produce hydrogen gas, which they’ll pipe away into a tank, and the other will bubble with fairly pure oxygen. It’s elementary chemistry, and Yinsen is both bemused and vaguely ashamed to have missed it. Then again, Stark is the engineer here, and they never taught jerry-rigging in medical school.

It’s a good thing he and Stark have built some kind of working rapport over the past few weeks, though. Stark still is not very mobile, for all that the renewed morphine dose _is_ helping, so Yinsen assembles the device as Stark directs him. That mutual familiarity means that, instead of the frustrating disconnect they’d wrestled while trying to draft those first few blueprints, the electrolysis device has come together with some kind of fluidity.

In fact, Stark is eyeing it now, appraising the electrode-brackets with a careful, drug-clouded eye. He drags one hand off the cot and reaches across, trembling a little, to brush sweaty fingertips over the joint that Yinsen just finished gluing. “Solid,” he rasps finally. “Good.”

Yinsen tilts his head in acknowledgement and puts the epoxy on the table right under the hole, high up in the cave wall, that passes for their ventilation system. Somewhere in there, a fan always whirrs; it should carry away enough of the fumes that Stark won’t choke on them.

“Hang the electrodes next,” Stark tells him, tipping his head towards the assemblage of metal and wire that sits ready on the nearest workbench. Yinsen picks it up, and under Stark’s direction, spends the next five minutes clipping the wires onto the brackets so that the electrodes will dangle at just the right position. Once he’s finished, Stark eyes their work again. “Good,” he decides, and closes his eyes.

“Only the collection tubing now, if I recall correctly.” Yinsen’s already gotten up to find the materials.

“Yeah. Rubber tubes, bell bottles, empty g--” He chokes back a cough. When he opens his eyes again, Yinsen’s standing over him with an armload of rubber tubes; the bell bottles, empty gas canister, and the rest of the materials are arranged on the workbench. “That,” Stark concedes. “Bottles first, bring ‘em over.”

The collection system is not so much more difficult to assemble than the electrodes themselves, and in another fifteen minutes, the device is complete. Yinsen checks the valves on the gas compressor and hydrogen cylinder one last time, then steps back to take it in. It’s an awkward, motley device, but it should do the job.

“Well, only one way to test it now,” he muses.

Stark grins. “Hit me,” he challenges, and settles the oxygen mask on his face.

With great ceremony, Yinsen stretches his fingers, then reaches for the on-switch. At first, nothing much happens, but then small bubbles start to break the surface of the water. Within a minute, both bell bottles are frothing merrily, and the compressor’s hum reverberates off the walls.

Yinsen smiles. “It looks good, Stark. How do you feel?”

No answer. Concerned, he turns to face his patient. “Stark?”

Stark is lying very still on the cot, staring up at the ceiling. He looks almost calm at first glance, but when Yinsen looks closer... Stark’s hands grip the edges of the cot, tendons corded across the back of his palms. He stares straight ahead, eyes flickering to follow something only he can see; he pants, wet and harsh, barely restrained. Most damningly of all, his forefinger twitches, metronomic, tapping out a heartbeat that’s racing in jackrabbit terror.

_Oh, no._ Yinsen drops to his knees beside the cot, resting his hands lightly on Stark’s shoulders. “Talk to me, Stark.” He can’t use most of the traditional exercises to break a flashback; reminding Stark of where he is, or what he’s wearing, or whether he can feel the device in his chest, is not very likely to help.

“Yeah,” Stark gasps. “What.”

Thank God, he’s not completely dissociated. “You’re all right, Stark. You’re safer here. Breathe with me, yes?”

Stark hacks out something that might be a laugh, and his tapping, impossibly, accelerates. “Breathe -- ! No, that’s -- it _smells_ like --”

Oh. _Oh._ Yinsen shuts his eyes. All the water in these caves must come from the same source, bear the same minerals and contaminants. Stark’s oxygen is bubbling out of the same water that drowned him. He’s _engulfed_ in the smell of it.

Clearly, breathing exercises are not the answer.

He casts wildly around the cave. There must be something -- _aha._ He squeezes Stark’s shoulder once -- “I’ll be right back” -- and darts across to the washbasin. The thin liquid dabs easily onto one of their cleaning rags, and although Stark gulps and twitches when the doctor tucks it under the edge of the mask, he doesn’t try to fight in earnest.

After a long moment, his fingers start to relax. The tapping slows, begins to peter out. “Aftershave?” Stark grunts, his eyes slitting open.

“Smells different, doesn’t it?”

Stark huffs, lips twitching in some approximation of a smile. “Yeah.” His eyes close again, and he lets go of the cot entirely, relaxing back into the scent of astringents and mint. Slowly, his breathing evens out, steady but for the unavoidable hitches of pneumonia.

Yinsen lets him rest. God knows he needs it, and the doctor can use it instead to gather a new set of tools. Stark will need a distraction when he wakes; the menthol can only go so far.

When Stark opens his eyes again, Yinsen’s back on the stool beside him, scanning a stack of onionskin paper. He nods in answer to the engineer’s half-smile, launching in without preamble. “I was wondering, Stark. How exactly do you plan to handle the sheer weight of this armor? I can see that it has engines of its own, but I do not quite understand how you intend to control them. There’s hardly any trigger mechanisms in the gloves, much less the boots...”

Stark lifts an eyebrow, and his smile goes a little toothy. “Hoped you’d ask. You’re l-- looking in the wrong place.” He draws one finger down the length of the shin-plates. “Control’s in the limbs themselves. Ever heard of -- haptic feedforward?”

Yinsen looks up from the drawings, catching Stark’s eye, and puts all the challenge he can muster into his raised eyebrow. “Show me.”

\---  
\------  
\---

**Notes for the Chapter:**

> Reviews are hydrazine. Fuel the author. :D


	13. Phase Shift

**Summary for the Chapter:**

> _His finger smoothes down the worn curve of the cutters’ handle. He has been_ fantasizing _for_ days _about getting back to his tools. He has_ plans _for these tools. Doc does not get to take his tools._

**Notes for the Chapter:**

> (phase shift: the transition from one state of matter, such as a solid, to another, such as a liquid or gas)
> 
> Only three more chapters to go...
> 
> As always, my betas are indispensable, and possibly the only reason this fic is still moving. MountainRose, szzzt, and keroseneSteve -- I couldn't do it without you guys.

"All right. Steady... steady... There you are."

"Not -- a horse, Doc."

"You wobble like a newborn foal, so forgive me the comparison." Carefully, Yinsen loosens his grip on Stark's rope belt, lowering the man's weight back onto his feet. He's gratified to see Stark's legs handle it with minimal trembling. "Oxygen?"

Stark twitches an elbow, nudging Yinsen's side with the hand that holds the mask over his face.

"Good. " Yinsen shifts their weight a little, tucking Stark's back closer against his chest, the better to gauge the rhythm of his patient's breathing. Shallow, stuttered, but better than it has been: it will be enough to keep him upright, probably. Assuming that he doesn't overexert himself immediately. "Need to cough?"

Well, that's interesting. Yinsen hadn't thought it was possible to roll one's eyes so hard as to make it palpable to a person standing directly _behind_ oneself. If anyone could manage it, though, it _would_ be the man capable of putting a sentence into the set of his eyebrows... "M'fine," Stark grumbles.

"All right, then. Your chair is over there."

Stark tilts his head as if to meet Yinsen's eye, his whole body telegraphing annoyance. "Like I -- don't _know?_ C'mon. Let's go."

Walking Stark the few meters to his chair is easier this time than it was when he first stood up, right after the surgery, but Yinsen can't let that sunny comparison outshine the fact that Stark should be able to do it by himself -- that he _did_ do it by himself, less than a week ago. When they finish lowering him into the chair he's wheezing again, clutching the mask to his face and trying not to double over; muscles tremble under Yinsen's palm. At least the gasping stops quickly this time, easing into long, steadying, controlled breaths.

"Okay." Stark lifts his head and surveys the contents of the table. A fond, sly smile twitches at the corner of his mouth; his gaze rests on each tool and coil of wire and sheet of paper in turn, acknowledging them one by one. He moves one hand, careful but steady, to caress the handle of the soldering iron. "God, I missed this."

Yinsen sits back from the table and lifts an interrogative eyebrow.

"Building stuff. Been bored, you have no -- no idea." His fingers stroke the tool's handle, up and down, before finally curling around it; he looks up at Yinsen, and his grin is blindingly real -- blindingly _alive_. "Finally gonna get to _work."_

\---

Grip the pair of 18-gauge wires; tuck them in place against the contacts of the tiny servo, liberated from a former life adjusting missile fins. Solder the connections down. Once the beads have set, swap soldering gun for wire cutters, measure, and clip the leads to size. Coil the trailing ends around a forefinger and tuck the whole thing aside. One down, five to go.

He's making sure to leave plenty of excess in the leads on these things. They're part of the trigger mechanisms for his ill-advised propulsion system, whose wiring will have to pass through the Suit's knee, hip, and probably shoulder joints. The knee's the real problem; he's still working on good ways to lock the mechanism for flight, stiffen it enough to take the thrust so his legs don't have to, without closing all the wiring channels in the process. This would be a hell of a lot easier if he had some way to shape carbon fiber without destroying it on a _primitive charcoal forge_ , but, well, _cave_ , he's got what he's got.

Tuck. Solder. Swap. Measure. Clip. Coil. Two down.

He does have a few good ways to seal a container, though. Could do this with hydraulics -- god knows there's enough compressor power lying around -- maybe by filing off enough iron into the lubricant to make it ferrofluid, then locking it up with a handy electromagnet. Not that he actually wants to hang his survival on yet another magnet, but screw irony, it's the best idea he's got so far.

Tuck. Solder. Swap. Measure. Clip --

\-- warm hand on his shoulder, and he jumps about a foot. Dropping the wire cutters, he wraps one arm around his ribs, cursing breathlessly. "Shit! Doc -- what the hell! Warn a -- guy!"

"I did. Five times." Oh, that eyebrow is _audible._ "You seemed to be enjoying yourself."

"Well, not -- _anymore."_ Yeah, he _had_ been enjoying himself. The blissful focus on triggers and joint designs had fuzzed out the cave; it was just him and the project, everything else drifting aside to let him work. Really damn nice, right up until somebody sees fit to _shock him out of it._ "What?"

Yinsen flicks his eyes in the direction of their cots. "You've been up for half an hour now. Time for a rest, don't you think?"

No. No, he does _not_ think. Tony's other hand tightens on the needlenose pliers. "M'okay, Doc." He lets go of his ribs to wave a hand across all he's accomplished in the past half-hour. "I'm fine. I'm working. Don't knock it."

"And you'll _continue_ to be fine, provided you rest when you need it." Doc reaches across the table, aiming for the wire cutters. "I'll clean up if you --"

_Oh no you don't._ Tony snatches the cutters back up and draws them into the shelter of his body, glaring sideways at Yinsen. "Like hell. I'm _fine."_ Besides, he's been lying flat on his back for _days,_ dying of boredom when he wasn't dying of worse things, and now that he finally gets to sit up Doc expects him to go _back?_

His finger smoothes down the worn curve of the cutters' handle. He has been _fantasizing_ for _days_ about getting back to his tools. He has _plans_ for these tools. Doc does not get to take his tools.

Yinsen sits back from the table, peering at Tony with an unfamiliar expression. "All right, Stark," he says finally.

"Look, I said no, I'm not --" Tony blinks. "Wait. What?"

"All right," Doc repeats, getting up from his stool. "If you don't feel you need to rest, I will trust you."

"What, really? Finally." Tony huffs in mingled amusement and triumph, turning back to the trigger wiring. He stills again, though, when a pair of steady hands come to rest on his shoulders. "...Doc?"

"You do still need to stretch. _That_ I'm not going to let go. If you'd prefer to do it here, that's fine, but you'll find that suit a difficult thing to operate if you heal with a permanent hunch."

He should've known better than to think Doc would give in _all_ the way. _Small victories, Stark. Take what you can get._ "Sure," he sighs. "Hit me."

The hands on his shoulders squeeze gently for a moment, whether in comfort or warning he's not sure, before their grip firms up and draws Tony's torso back to plant Yinsen's hip squarely between his shoulderblades. He huffs a little, remembering where this is headed and not liking it one bit, and yep, they just keep _going._ The steady pressure almost feels good at first, pulling his collarbones apart and stretching muscles cramped from weeks of hunching over his chest… but he's been curled up like that for a _reason,_ and the pleasant burn quickly gives way to something a lot less enjoyable.

He bites down hard on the groan that wants to emerge. Noise would be a pointless waste of air, and hard experience has taught him that gasping for breath in this position is not fun at _all._

"Easy," Yinsen murmurs. "Breathe through it."

_Dammit, Doc._

Yinsen counts off a rhythm to breathe to, though, and after a few false starts he manages to fall into it. In, and the bellows-frame of his ribs pulls his chest wall taut; out, and the burning stretch dies down to an ash-veiled glow. In. Out. It's weirdly hypnotic; when Yinsen lets his shoulders relax, thirty seconds' rest between stretches, he has to shake himself a little.

After the fifth rep, it's more than thirty seconds' break. Tony shakes himself out of a reverie lit by charcoal glow, clearing his throat. "We done?"

"For now. You'll need to do this again in an hour or so."

Good thing he can do it without getting up, then. Tony grunts noncommittally and flexes his wrists, flipping the pliers around his index finger. "Right. Come get me in -- an hour, then." These servo leads aren't gonna fix themselves.

Instead of going off to whittle at random, though, like he's been doing the last day or so, Yinsen rounds the bench and perches on the stool next to Tony. Agile doctor's hands flex the skeletal hinge joint he's pushed off to the side, watching its interior spaces change shape with the movement. "Elbow joint?" he asks.

"Knee, actually." (...clip, coil, three down.) "Needs some work, still. Might want to -- pick your brain, when I've got these ready."

Yinsen flexes the joint again, this time deliberately catching one finger in the closing space. "Hmm," he murmurs, and reaches for a pencil.

A couple minutes later, when Tony scoops the completed servos into a tray for later, he finds Doc scribbling away at… Huh. "Hadn't pegged you for a da Vinci."

Yinsen rolls his eyes. "These are joint diagrams, not the Vitruvian Man."

Tony cocks an eyebrow, leaning carefully closer. "Thought you were -- a cardiologist."

"Specialty does not imply ignorance." A quick arc sweeps the space between the sketched-out calf and the back of the thigh, '178°' noted in that neat angular hand. "Besides, I have my own full set to examine, you know."

Tony manfully shoves aside the innuendo that rises unbidden to his tongue (wow, he _must_ be doing better, if those impulses are back online) in favor of parsing the diagrams a bit more closely.

Hmm. Yes. That _is_ helpful. Especially with struts shaped like that… and the space'd be roughly ellipsoid…

A _ha._

He takes one more good long look, to etch the details in his memory, before snatching his own sheet of paper and going to town. The joints'll work _this_ time.

\---

Copper coil, ten-megohm resistors, dorsal half of a dissected Melchior rocket, another pair of aluminum struts, box of LEDs, and _go_ \-- Yinsen scrambles back across the cell, dumping the double-armload of parts on the bench at Stark's elbow. His alacrity gets him a vague grunt from the figure hunched over the table, blending into the rattles and scrapes as Stark snatches his offering and starts working it into the… whatever he's building. It started as wiring for the new joint designs, he thinks, but it has since proliferated into an indecipherable, chaotically organized mass of machinery. The thing sprawls across two benchtops and a table, trailing loose wires and bristling with joints that connect to nothing; for all its chaos, though, it's somehow hauntingly systematic, as if its loose ends could articulate with each other at any moment and draw the whole thing together into a cohesive whole.

Stark's been working on it for hours now. At first, Yinsen had been able to follow him, and to interrupt at intervals with stretching exercises and conversation. Gradually, though, that driving focus had come over him; the conversation had petered out, the stretches interrupted by restlessness, and eventually Yinsen gave up even trying to break into Stark's concentration. At this point, he's just trying to stay out of the way.

"...hm… Hey! Driver, you know the one -- five-eighths, red handle, c'mon."

That, and play gofer, when Stark demands it. A quick rummage through the scattered tools comes up with the one ordered, and he slaps the handle into Stark's outstretched palm.

"Mm, thanks Dummy. Not a wine rack."

He's not sure _what_ to make of the name-calling, though -- much less of the word-salad occasionally tossed out in the tone of a dry, distracted compliment. Maybe he should try to interrupt again, just long enough for a neurological exam. Hopefully it's just Stark's usual indecipherable mass of pop-culture references, but he'd rather weather the man's annoyance to prove it harmless than risk standing aside while Stark has a stroke.

He's only just resolved to check and begun moving, though, when Stark suddenly pauses, staring intently into the struts he's articulating. "J, modeling," he commands, looking up at -- well, not so much _at_ as _through_ \-- the ceiling. "Gimme Young's modulus for this third permutation, then torsion and compression se --"

He cuts off in mid-word, his eyes snapping into focus on the rock above him, and flinches back as if struck. His eyes jolt wide open, bewildered and lost, and dart across the cave; his hands twitch and nearly drop his tools.

It's only a moment before he stills, though, fingers curling slowly around the handles. "Oh," he manages, staring down at his workbench again. He buries his face in one palm. "Fuck."

Yinsen moves in beside him, resting a hand (slowly, predictably) on his shoulder. "Stark?"

A harsh shudder jerks through Stark's entire body, and he drops his tools to plant his face in both hands. His answer takes a while in coming, and it's muffled through his palms: "M'fine."

"You're a terrible liar."

"Just…" Stark scrubs both hands down his face, blinking hard. "Zoned out a bit. I'm back, it's fine."

Yes, and Yinsen is king of the moon. He sits down beside Stark, keeping the hand on his shoulder to ground him. "I had an intern, you know, back at my hospital," he muses. Perhaps if _he_ shares, Stark will feel safer in reciprocating. "A good man, good with sutures, excellent bedside manner; he was very kind. A little disorganized, though. He was forever losing important paperwork." He cracks a small half-smile, remembering how Rajid had flailed about in search of the latest missing chart, half-panicked and trying so very hard to hide it.

The smile fades, though: "The first time I had to dig a bullet out of one of Raza's men… when I called for the sutures, I called for my intern. He'd been dead for three weeks."

"Ouch."

"Mm." Yinsen tilts his head a little, chasing Stark's gaze. "I was lucky they didn't take it personally. I'd used his nickname, which sounds extremely rude in Dari."

Stark looks away. "I called you Dummy, didn't I."

"Both 'dummy' and 'butterfingers.' I thought at first that I'd dropped something without realizing it."

The choked noise that piles up in Stark's throat is neither laugh nor sob. "If _those_ two were around, you wouldn't be able to -- miss it. Disasters, both of them. I should've broken them down for -- for parts, years ago."

Yinsen blinks. "Parts?" he ventures.

"Build them into a refrigerator or something. 'Cept they'd always screw up your drink." Stark combs his fingers roughly through his hair. "The morons don't have the RAM to handle cleaning up -- one damn workbench -- and they still won't, won't let me upgrade them. Dummy _likes_ his damn 1989 m-motherboard." He huffs, breathless, and curls an arm around his ribs with another little sobbing laugh. Scruffy dark hair curtains his eyes. "Stupid piece of crap."

Robots. Stark's lab assistants are robots. (Yinsen should probably be surprised about this, but all he can manage is a distant, wry half-amusement.) They seem to be more than his lab assistants, too; for all the casual vitriol of his words, Stark's voice is warm, and he's visibly fighting back tears. Yinsen has no better way to describe it than _paternal_ \-- a worried father missing his children.

The madman's built himself an artificial family. Yinsen has no _idea_ what to make of _that_ … and he quickly pushes aside the little voice that wishes he had the same capacity.

( _Stark's_ children can be _re_ -built, after all.)

\---

Yeah, he's officially messed-up, if even talking about the bots is doing this to him. Tony drags a sleeve across his face and draws a deep, steadying breath. _Pull yourself together, Stark._ "Anyway. Yeah." He stares down at the core torso assembly in front of him, flexing a strut between thumb and forefinger.

He isn't going to get that modeling done, is he? Without J (don't think about it, not helping) and his home systems, he'd have to code the whole sim environment from _scratch_ on a laptop that might actually be older than he is. No mockups, either, not under the camera's wary eye.

Pencil and paper it is, then. It's crude and it's imprecise... but then, this thing only has to work once.

Without another word, he throws himself back into the work. In the rhythm of construction, he can lose himself again. When he's wiring this colossal kludge, he isn't missing his idiot boys. It's hard to be homesick when you're busy. The core torso wiring's almost done, now; he can start hooking it into the leg drivers tonight, get that done by tomorrow. Haptic sensors after that, and soon. Valves and jets for the flamethrowers, rocket rails, joints and locks. It's all coming together.

He turns away from the camera, so it won't pick up his predatory smirk. _A few more weeks, assholes. Just wait._

\---  
\------  
\---

**Notes for the Chapter:**

> I feed on critique. It's delicious. Om nom nom reviews. ;)


	14. Annotation

**Summary for the Chapter:**

> _“So you are a man who has everything… and nothing.”_

**Notes for the Chapter:**

> (annotation: an explanation, comment, or clarification added after the fact)
> 
> It lives! No, I haven't forgotten about this, I promise. This chapter was just very difficult to write -- you'll see why -- and Real Life didn't help matters either. With any luck (and any semblance of sanity), the next one won't take nearly as long.
> 
> I still owe a _lot_ to my betas, MountainRose, Szzzt, and keroseneSteve. Broken record I may be, but this fic really would be dead without you guys. Thanks so much!
> 
> **Warning for this chapter:** Suicidal thoughts. Sort of. It's close enough to make me add that specific tag, that's for sure.

Yinsen's whittling again.

He's been doing it off and on for the last few days -- scrounging bits of wood and shaving them down to some particular size. There's a spare box next to the head of Yinsen's cot, and it's gradually filling with a jigsaw jumble of neatly-shaped parts. He's building something.

It's not for the Suit, Tony knows that much. For one thing, there aren't any wooden parts like that in the plans. For another, Yinsen only works on it when they have downtime -- at night, sometimes, or while they eat, or when Tony's too tired or drugged-up to do anything useful. Maybe it's something personal.

Today's work isn't quite the same as the last thing Tony watched him make. So far, most of the parts have been wide slabs or narrow slats, pieces of a broad shallow box. Today, though, the guy's got a sliver-thin piece of veneer, and he's scoring it delicately along very straight lines. Flat on his back, drifting in a post-PT morphine haze, Tony makes his eyes focus enough to watch.

Triangles. He's cutting it into slender isosceles triangles. The shapes dredge up a vague sense-memory -- cafeteria tables in a college hall, cheap plastic game boards, a fugue of strategic concentration and a beer at his elbow. MIT. Backgammon.

...Huh.

When Yinsen finally says something about it a few days later, Tony affects nonchalance. It's not _that_ big a deal, anyway. Doc only just proved, in one stroke, that he's got the good taste and strategic sense to play backgammon _and_ the woodworking skill to make the board himself. (Out of Lebanese cedar, no less, and how the hell did he get the Rings to bring him _that?)_

Hidden depths, Doc. Hidden depths.

Over his shoulder and out of the corner of his eye, he watches his cellmate assemble the board. For all that Tony calls it "crappy" when Yinsen finally mentions it to him, it's not a bad piece of work; lacking nails, and reluctant to dip into their glue supply, the doctor puts most of it together with elegant mortise and tenons. Tony kind of wants to see what he'd do with actual tools... He must have some kind of workshop at home, to keep his skills this sharp. What's _that_ setup like?

Maybe, when they're out of here, Yinsen can show him.

\---

Stark's watching him again.

He's been doing it off and on for the last few days -- sneaking glances and gazes when he thinks Yinsen won't notice. When they're working together, nothing is different -- Stark checks his work openly and comments out loud -- but when they've settled down to rest, and Yinsen picks up his woodworking tools again, Stark's gaze becomes a furtive thing. If he didn't know better, Yinsen would think the man had never seen a penknife before.

The best response is probably no response, he supposes: Stark will speak up when he's ready. If he's ready. Until then, Yinsen can focus on building this board.

He selects another slice of cedar veneer and begins marking the desired pair of triangles on its surface. It'll be a good board, for all the privation and fear that went into its building. He still remembers how to do this; he could probably do it blindfolded. He'd take a finger off at some point, but it would still work.

He glances over at the parts stacked on the workbench beside him. It reminds him of Stark's plan, actually: simple, foolproof in theory, and monstrously risky in practice. On the one hand, the Suit -- Starktech even if it's makeshift, with hydrazine flamethrowers, armor forged from missile plating, and an exoskeleton to turn each arm-sweep into a sledgehammer blow -- seems the obvious bet to win out over last year's hand weaponry. On the other hand, the Suit -- cobbled together from scraps, with a twenty-minute preparation time, a faceplate whose eye-slits will cut vision down to slivers, and its motherboards and cooling systems mounted naked on its back -- is all too likely to trap Stark instead of saving him. Their safety margins are razor-thin.

It's a terrible plan. Yinsen might even have called Stark out on it if he had any better ideas.

Slivers of wood fall away from his knife, and he wonders idly what their chances are. The armor is their best chance, so Stark will be better off... _if_ they can get him into the suit fast enough. There are far too many variables. There are far too many ways this can go wrong, and any one of them will end with a Starktech bullet fired up through the chinks in the armor.

And those are _Stark's_ chances. If even one man slips by the iron titan, Yinsen will be horribly exposed.

He's not going to survive this, is he?

The penknife slips; Yinsen sets it down with shaking hands, overcome by a tangled rush of emotion. He's going to die. All these months kidnapped and terrified, never knowing when he'd be murdered for failing to save some terrorist or for saying the wrong thing or just for sport, knowing he'd never be free again, always wondering whether this would be the moment his life just fizzled out... and now he knows. He'll die on the day they escape.

Why is it such a _relief?_

It's the not knowing, he tells himself. Living like he has been, where a pointless death could take him any moment -- it's hell. Any doctor worth his salt knows how stressful such a life is. He's just relieved to know when it'll be over.

That, and the fact that he won't die for nothing. He'll be giving his life for Stark's -- he, of all people, will be a martyr. He clamps down on a surge of hysteria. _Him,_ inveterate skeptic, scientist, half Westernized... _Who are you kidding, son of Shayan? You never stopped believing._

He'll be a martyr. He might even go to Heaven.

He'll see his _family_ again.

Yinsen bites down hard and only barely manages to hold back a sob. His fingers tighten convulsively on the sheet of cedar, but the earthy incense-scent of the wood doesn't help to ground him -- not when all he can think of is the cedar woodchips on his workshop's floor, his father's penknife in his son's uncertain fingers, his wife's radiant smile when they'd presented her with the new backgammon board... Its joins had been a little lopsided, scored too deep here and there, but Mehri had understood: _there's laughter in the varnish,_ she'd said, running her fingers along its glossy rim. _Laughter and love._

That board burned with the rest of Gulmira. When he searched the wreckage, there was barely enough left to tell its ashes apart from Fahran's. Just a dovetail join and one crooked triangle, half-buried in the stinking char that had been his son -- his son and wife and daughter mingled where they fell, together at the end, and _why hadn't he been with them -- ?_

Yinsen shivers, gasping in a breath he hadn't known he was holding, and when it shudders back out it's a sob he can't hold back. He clenches his teeth and bows his head, eyes squeezed shut --

Stark clears his throat.

The doctor's head snaps back up. Stark is lying half-propped on one elbow, staring pointedly at the wood in Yinsen's hands. "You're not gonna get very far if you keep trying to cut along the grain like that."

...What? Yinsen stares back at him, nonplussed, and swallows against the grief locking his throat. "I don't --"

"It's just gonna split on you. Unless that wood's cured really nicely, it'll just break open along the grain and --"

_"Stark,_ I don't--" Yinsen sucks in a breath through his teeth, irritation warring with grief. "I don't want to discuss this," he manages.

"-- do you really want to try gluing down a handful of splinters? ‘Course you don't --"

He's not even... is the man actually _blind?_ Yinsen frowns. "I'm--"

"-- I mean, it's not like you have a lot of extra material --"

"...Stark."

"-- so seriously, just turn your pattern, cut the other way --"

_"Stark!"_

The other man finally, finally shuts up, raising one infuriating eyebrow. Yinsen takes full opportunity of the chance to get a word in edgewise. "I'm _not cutting with the grain."_ He holds the cedar sheet up, pointedly getting it closer to his patient. "The grain runs _this_ way. I am cutting _here._ Even if you _were_ making sense -- and you are _not,_ because this is good hard cedar and it will not split like some kind of _pine_ \-- you would still be wrong because I am _not even doing what you think I am,"_ he snaps.

That eyebrow doesn't so much as twitch. "So you weren't. Right. I knew that. How are you gonna get the veneer to stay down, though, without any decent glue? It..."

He trails off as Yinsen snorts and gets off his seat, throwing up his hands in annoyance. "Is it time to get back to work yet?" he snaps. "I think it's time to get back to work." He stalks over to his patient, checking Stark's pulse and pupillary reflex; the man tugs his head back with an indignant noise when the light hits his eyes. "You're fine. Come on, rise and shine."

Stark grumps and grumbles as Yinsen hauls him to his feet, but he does come, and within fifteen minutes they're both absorbed again in the building.

The day passes in a whirlwind of wiring and assembly, shop talk and jabs traded. Stark doesn't say another word about any of it -- woodworking or backgammon or the way he'd watched Yinsen break down -- and slowly, the tangle of irritation and shame and grief fades to the back of his mind. He's distantly impressed, really: he never would have thought Stark subtle enough to distract him like that. By the time they cut the welding torch's flame, pack away the hand tools, and roll up the blueprints, he's more amused by Stark's maneuvering than anything -- amused and even a little grateful.

When night falls at last and he settles down on his cot, though, something glints in his peripheral vision. Puzzled, he leans back up, peering down at his pillow. Two small piles of metal glimmer in the dim fluorescents: fifteen matched nuts and fifteen matched washers.

Backgammon pieces. Well, he did say he wasn't sure what they'd use.

A small, lopsided smile nudges the doctor's lips. This is the man he's to die for, is it? Well, then. He could do worse.

\---

"Backgammon, Stark?"

Tony turns, startled. His arms are still full of welder tank, and he almost has to juggle his gloves to keep from dropping them. "Huh?"

"Backgammon." Doc's standing behind him, only slightly sooty, with a teacup in one hand and his backgammon board in the other. When he waggles the teacup invitingly, nuts and washers rattle inside. "Care to play?"

"Um. Did you already -- ?"

"Yes, it's finished. I set them aside to anneal, over there."

Tony glances. Yep, the actuator casings he had Yinsen working on are fully coated, lined up on their makeshift rack and placed a careful eighteen inches from the furnace's flank. They'll need to be moved in a few hours, but...

"And you appear to have finished building their mounts, if I'm not mistaken." The doctor nods towards the neatly-paired set of leg struts laid out on Tony's workbench.

He's right, or Tony wouldn't be putting the welder away. The engineer snorts and unloads the tank into its designated corner. "Yup."

"Which means that we have at least four hours before we can do much of anything."

Right again. Tony'd tried to avoid bottlenecks when he planned out the construction process, but there was no good way around this one: past this point, they can't assemble much of anything until they can build the skeleton of the leg drivers. Which, of course, they can't exactly start while the coating on the actuators is still hot enough to burn leather. He raises an eyebrow at Yinsen. "Yeah?"

Doc waggles the teacup again, rattling metal on ceramic. "Time enough to see how MIT and Cambridge match up, isn't it?"

...Oh, it is _on._

\---

"So do they have backgammon championships at Cambridge too, or did you just learn for the hell of it?"

Yinsen finishes counting out one set of washers before looking up. "I learned as a boy, actually. It's a popular game, where I'm from." Five more markers on the next spot.

Stark hums, idly rattling his teacup with its pair of makeshift dice. "Where's that?"

Yinsen just flicks his gaze up over the rim of his glasses to pin the engineer. Stark's been unusually chatty for the past few days, ever since Yinsen found his scavenged set of game pieces. They talked before, yes, but mostly about the immediacies of their situation -- medicine, engineering, their captors, cave survival. Now, all of a sudden, his patient wants to know about his childhood and his hobbies. It's vaguely disconcerting, all the more so because it's also so endearing.

He sets the last of the game pieces in place. "There we are. Black, or red?"

"You mean nut or washer?" Stark leans in over the board, nicely steady even when the motion must stretch his healing muscles. He's down to half his original morphine dose, and only as needed, but it may even be time to cut down again. "Red. Washer."

Which gives Yinsen the first move and the handicap. He probably deserves that, after assuming Stark wouldn't even know how to play. He chuckles and nods. "All right. Pass the dice?"

That's the last word either of them speaks, other than to read off the dice or indicate a move, for the entire first game. They both spend it sunk in concentration, calculating each other's strategies and working out their counters. It's a close game -- morphine or no, Stark would not appreciate Yinsen going easy on him -- but neither of them is particularly surprised when Stark actually wins.

"Good game." Yinsen surveys the board, eyebrows raised. The man is definitely better than he'd expected; he must have practiced since his college years, to keep his skills so sharp. Who does he play against, at home? His robots? _That_ would be a game worth witnessing.

Hidden depths, Stark. Hidden depths.

"Want to go again?" Stark flashes him a smug white grin.

Well, why not? Yinsen glances up at the rack of actuator casings, pinging softly now and then as they cool. They won't even be ready to move for another hour. "Let's."

They reset the board together this time. Stark takes red again -- takes the washers, at any rate -- and passes the dice to Yinsen. "After you."

The dice rattle in the teacup, and then on the board: eight. Yinsen picks up the first of his pieces. Prime or blitz? Stark broke a prime lineup last game without batting an eyelash, so perhaps Yinsen should play more aggressively this time...

"Why'd you come back, Doc?"

Startled out of his musings, Yinsen almost drops the nut. "Sorry?"

"Nice place, Cambridge." Stark taps one finger absently against the reactor. "Nobody tries to bomb the hospitals there."

Ah. American stereotypes. "There's more to Afghanistan than you see on TV," he explains mildly. "Some places are quiet. Peaceful."

"Oh?" Stark raises an eyebrow. "What kinds of places?"

"My home, for one." Yinsen hands the dice across. "Your move."

Stark takes the cup in silence, barely meeting Yinsen's eye. When the dice hit the board, he reads them off in Farsi; it's a good roll, but more to the point, his pronunciation's improving. It's an odd olive branch, but isn't that just like Stark? Yinsen accepts it with a wry smile and a word of praise.

Only when he's passed the cup back does Stark speak again. "Still haven't told me where you're from."

He walked right into that one, didn't he? Yinsen glances up over the rims of his glasses. As much as he does not wish to discuss his lost home... maybe there'll be peace in remembering it as it was. "I'm from a small town called Gulmira. It's actually a nice place." _Peaceful,_ he thinks, remembering the olive trees and the running water, silver in the sun.

Stark watches him, intent, as if straining to hear what Yinsen hasn't said. "Got a family?" he asks.

Yinsen's eyes drop; his throat clutches tight. Mehri's laugh like running water, silver in the sun... For an instant he can't speak. He'll hear it again, before much longer...

"Yes," he hears himself say. "And I will see them when I leave here.

"And you, Stark?" he adds. Suddenly he wants to know, to hear Stark describe the mad family he's built for himself. It's only fair, isn't it?

\---

A _family?_ Tony Stark's family? It's almost laughable, at least for the second before you realize how pathetic the concept is. His mother is dead; his father is a bastard, and also dead; their family is distant or gone. The only people in his life are his AIs, his employees, and his one-night stands; even Obie works for SI. The only friends he has, the only people he can trust to stay with him, are bound to him at least as much by their programming or their paychecks as by any affection they might have for _him._

Tony ducks his head, feels his lips twist. Does he have a family. What kind of a question is that?

"Nah," he finally manages with an abortive shake of his head. No. No, he doesn't.

Yinsen's face shutters, and suddenly Tony can't begin to parse the emotion there. Scorn? Pity? Some kind of... skepticism? Or is that a challenge? Tony thinks inexplicably of furnace coals: _a very important week._ "So you are a man who has everything... and nothing."

Tony attempts an ironic smirk and fails, unable to meet Yinsen's eye. That sounds about right, doesn't it? Poor little rich boy, hasn't got a friend in the world... it's ridiculous on so _many_ levels. How'd he ever get this far in life without making so much as a single real connection?

Something's nagging at him, though, and he steals a glance up at Yinsen. The doc's eyebrows are up, his whole long face drawn into the ironic expression. If he didn't know better...

Why can't he shake the feeling that Doc is calling bullshit?

A faint snort jostles him out of his thoughts. Dice rattle in the cup. "You call a person's name in your delirium, I have to think they mean _something_ to you."

Tony's stomach sinks. "Who..."

"Now that I know you weren't just insulting me..." Doc trails off. "Perhaps they need better names, had you thought of that?"

Tony blinks. Hard. "They don't want better names. I tried -- DUM-E won't answer to anything else, he takes it as an insu --" What the hell is coming out of his _mouth?_ He clamps down abruptly. "What, the _bots?"_ he manages instead.

Yinsen gives an elegant, one-shouldered shrug and tips the dice out onto the board. "In my experience, fever makes a man very truthful."

And what can he possibly say to _that?_

\---   
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[TBC]


	15. Stress Tests

**Summary for the Chapter:**

> _The Ten Rings don’t turn the lights off that night._
> 
> _Neither Tony nor Yinsen have time to notice._

**Notes for the Chapter:**

> (stress test: a test of a system's function when subjected to greater than normal amounts of pressure)
> 
> So... grad school. What the hell was I thinking, getting myself into this?
> 
> The fic isn't abandoned, just... progressing slowly. Glacially. Thank you, all of you, so very much for sticking with it all this time!

“Okay, sensors are on. Check the --”

“The connection is solid.” Yinsen wiggles it in its socket to demonstrate. “Go.”

“Right.” Tony cinches the thigh strap down one last time (he does _not_ want this thing falling off and shattering on the floor. They’ve spent entirely too much time developing the feedforward mechanisms for the Suit’s limbs, and this one’s the best of the prototypes; if it works as planned, he’s gonna want it intact to help copy his improvements to the rest of them) and takes a breath. “Going,” he announces, and straightens his knee.

On the bench beside him, the leg actuator straightens out with an obedient _bzzzhnk._

“Score,” he mutters, and tries it a few more times -- _Bzzzhnk. Bzzzhnk. Bzzzhnk._ \-- while cataloguing performance and planning a few little tweaks. The system’s working up to spec already, but it’d be nice to refine a few things. Maybe he can up the efficiency, cut out that noise…

“Have you ever considered designing prosthetics?”

“Huh?” Startled out of his plans, Tony looks up. Doc’s eyeing the leg actuators, his face a study in something Tony can’t place. Awe? Envy? “Prosthetics? Can’t say I have.”

“Perhaps you should look into it, when you’re home.” Yinsen catches his eye. “Designs like these could revolutionize the field.”

Tony blinks. “This? You’re kidding. I could’ve built this ten ye --” He cuts himself off at the abrupt realization that, well, _he could’ve built this ten years ago._ Another chunk of his life, wasted as the Merchant of Death; how many people did his talents kill, instead of giving them the chance to walk again?

Then again, this might just be a chance to even the scales a little, help some of the wounded survivors. He clears his throat. “That’s... actually a really good idea. I’m not real well up on the field, though -- you know anybody who could give me a crash course?”

Yinsen snorts and moves to help unstrap the feedforward sensors. “Do you ever ask questions whose answers you don’t already know?”

“Is that a yes?” Tony pulls his leg free and hops down off the table.

Doc just shakes his head, but they can both see the grin behind it.

They snipe back and forth as they settle back to work, Yinsen to tweak the other leg’s sensor rig, Tony to weld the brackets for this one onto the actuator’s frame.

_“Dsta bala!”_

Wait, what? Tony looks up to meet Goon Number Whatever’s eyes through the slot in their door. Yeah, they’ve got visitors. Hopefully it’s just Beardy with another load of laundry… but no, as he chokes off the acetylene and gets to his feet, the doors boom open and half the population of the cave system starts pouring in. He and Doc both get up, slowly raising their arms above their heads. What the hell…?

He gets his answer when the VIP of this little get-together finally shows up. Bald guy, jacket and robes, a heavy signet ring -- the sight of him hits Tony like cold water to the face. _Raza._ The brains behind this whole shitshow. He’d stood on the other side of That Barrel, watching from above as his goons shoved their prisoner’s head underwater again and again. His expression never moved, always the same glacial blank. Ice over stone.

Tony hasn’t seen him up close since… since he broke. Beardy always does the talking; Raza only shows up when shit’s about to get uncomfortably real. Call him paranoid, but Tony’s not real happy about seeing him again.

There’s actually something resembling expression on that face as he looks their cell up and down. When he looks to Tony and Yinsen, it’s… what is that? Mild surprise? “Relax,” he tells them, in perfect English.

What the… Tony glances over at Doc, but Yinsen looks just as puzzled and apprehensive as Tony feels. If even he doesn’t know what’s going on… yeah, Tony does not like this at _all._

As his prisoners lower their hands, Raza advances on Tony. Suddenly there are fingers at his chest, parting the front of his shirt, baring the arc reactor to the man’s flat, feline eyes. Callused, fever-hot fingertips trace the shape of it, scar tissue and smooth metal, and it’s all Tony can do to keep from jerking away. Raza’s touch is live snakes and barbed wire, something razored and buzzing that writhes under his skin. He’s talking again, still in English, but it might as well be Urdu for all he understands -- how could anyone _think_ like this? --

Finally, he pulls his hand back and prowls back into their gear. It can’t have been more than a few seconds -- he’s still monologuing, as if they don’t already know _exactly_ how thoroughly he could fuck everything up if he had Stark weaponry -- but Tony drags in air like he’s been running through a roomful of carbon monoxide. When the guy paces past him again, he can barely stand to look up.

Then he finds the drawings, and every muscle in Tony’s body jerks tight. He doesn’t even feel it. If Raza figures them out -- but no, Doc raises a quelling hand, and he’s right: Raza’s only got the top few sheets of the stack. They’re safe, at least from that.

But suddenly it’s an interrogation again, and it’s _literally_ in Urdu this time. Tony can’t pick up more than a couple scattered words -- _fail, repay, live_ \-- but it doesn’t take a polyglot to feel the tension. Doc is a terrible liar. Shit. They’re in trouble now --

One sharp word, and the Ten Rings are forcing Yinsen to his knees.

Tony stares at them wildly. It doesn’t take a polyglot to recognize threats, either -- especially not when they’re still red-hot, fished straight out of Tony’s own forge.

They’re forcing Yinsen’s mouth open.

Oh god, no. _No._

\---

The coal is a fragment of Hell itself, roasting the skin of Yinsen’s cheek even from ten centimeters out. There’s a vice-clamp of a hand pinning him to the anvil. He’s going to die. He’s going to die, and it won’t even be for any good _reason._ He’s not ready, they’re not ready!

He’s pleading automatically now, nothing in his head but Raza’s barked demands and the searing death inching ever closer. He knows exactly what it will do to him. Third-degree burns, and worse, to those delicate tissues -- it would break anyone. Not that it will work as an interrogation technique, he thinks wildly: after _that,_ it’d be a miracle if he could still speak. But God, oh God, it’s still getting closer --

“What do you want, a delivery date?” Stark’s voice slices through the clamor. “I can --”

He draws up short when the entire mass of their captors whips around as one to ward him off. Even Yinsen twitches, trying to rise against the hand on his skull. If the man gets himself killed now -- !

Instead, there’s an instant of silence. Stark swallows. “I need him,” he mutters. “Good assistant.”

The coal pauses in midair. Another silence.

The _clang_ as it hits the anvil, two fingers’-breadth from Yinsen’s lips, reverberates through his entire being. Relief turns his joints to water; he sags over the iron. Somewhere, Raza tosses the pliers away with a crash, but he barely registers it, or the last few words exchanged, or the footsteps and the groan of the lock.

Stark’s hand on his shoulder pulls him back. “Hey. Doc. We gotta move.”

So soon? Yinsen can hardly contemplate moving. He bites down a small noise of protest, pushing himself up off the anvil instead, to kneel beside it. The coal still smolders on the iron; he scrubs his hands over his eyes to block out the sight.

_“Doc._ Come on, don’t look at it.” Sound of metal on metal, and then a dull crackling _whump:_ the menacing radiant heat is suddenly gone. Yinsen looks up to see Stark pulling the tongs free of the furnace. “Don’t let it get its claws in you. Let’s go. I’ll do the hot work, just -- we have to _move.”_

“What?” Yinsen manages.

“Did you not hear -- of course you didn’t, you were… distracted. Shit. He…” Stark trails off, swallowing hard. “He wants the missile by tomorrow.”

An electric jolt flashes through him, jerking him straight upright. _“What?_ That’s -- that can’t be more than ten hours --”

“Yeah.” Stark’s fingertips beat a fierce tattoo against the arc reactor. “We’ve got a deadline. _Come on.”_

\---

The Ten Rings don’t turn the lights off that night.

Neither Tony nor Yinsen have time to notice.

\---

Tony’s been putting it off as long as he possibly can, but now there’s no choice: one way or another, he’ll have to forge the armor plating tonight. He hefts the rounder a few times, testing the weight against his healing muscles: it’s not too bad, at least. Not much _fun,_ that’s for sure, but the pain’s familiar -- the same deep stretching ache he’s gotten to know so well in PT. Nothing wrong there. Time to bite the bullet.

So he drops the hammer in front of Yinsen, just beyond the flamethrower parts Doc is mounting onto the forearm frames. Yinsen looks at it, then catches Tony’s eye over his glasses. His mouth is drawn tight and thin, his eyes pained, but he lifts his chin and nods. “Tell me if you need the drugs” is all he says.

They both know very well that that’s not an option -- Tony needs his head clear, now of all times -- but Tony just nods silently and heads for the forge, dropping off his jacket as he goes. He’s already had the welded plates on the heat, so it doesn’t take much to get the crudely-shaped proto-helmet ready to be worked. He positions it on the anvil and hefts the hammer again. He’s got this. Just push through it.

When he brings the rounder down, though, the first shattering strike might as well have cratered his own chest. He bites down hard on a startled yell, hand flying to the reactor; the hammer crashes to the floor. The edges of his vision haze white, and it’s all he can do to keep his feet without swaying into the red-hot steel.

Yinsen’s voice cuts through the haze. “Breathe, Stark. Easy. Breathe… easy, easy.” When he’s blinked back the haze enough to meet Doc’s eye, he catches the man glancing towards the morphine supplies. “Do you --” he begins.

Tony just shakes his head. “We’re on the clock.”

It’s easier the second time, at least, and the third. The sharp ache of lifting, the brutal stab of impact -- it’s not so different than breathing used to be. In, out, in, out -- raise, strike, raise, strike -- and every spike of pain a coin to pay the cost of survival. Gradually, he finds his way into the rhythm of it. Lost in the hammering tempo, he loses the line between himself and his work; he is the iron, shaping himself on the anvil before him.

The finished faceplate comes out of the quench bucket with a hiss like a live thing, and when he clangs it down on the bench in front of Yinsen, its baleful glower rakes them both head to foot. It’s as crude and ugly as the rest of this project, but there’s brutish strength behind it. (There’s one more reason to get out alive, Tony realizes: if he dies in this tin can, he’ll never get to finish the Suit, never chase its own gleaming future.)

(It would be fitting, somehow.)

Doc meets Tony’s eye with an unspoken question, and Tony grins. “One down.”

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**Works inspired by this one:**

  * [Stark (illustration)](https://archiveofourown.org/works/730643) by [szzzt](https://archiveofourown.org/users/szzzt/pseuds/szzzt)




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